U.S. patent application number 13/502002 was filed with the patent office on 2012-08-02 for resin composition, semiconductor wafer bonding product and semiconductor device.
Invention is credited to Hirohisa Dejima, Masakazu Kawata, Toshihiro Sato, Fumihiro Shiraishi, Toyosei Takahashi, Masahiro Yoneyama.
Application Number | 20120196075 13/502002 |
Document ID | / |
Family ID | 43876230 |
Filed Date | 2012-08-02 |
United States Patent
Application |
20120196075 |
Kind Code |
A1 |
Takahashi; Toyosei ; et
al. |
August 2, 2012 |
RESIN COMPOSITION, SEMICONDUCTOR WAFER BONDING PRODUCT AND
SEMICONDUCTOR DEVICE
Abstract
A resin composition of the present invention is used for
providing a spacer 104 having a grid-like shape at a planar view
thereof between a semiconductor wafer 101' and a transparent
substrate 102. The resin composition includes a constituent
material containing an alkali soluble resin, a thermosetting resin
and a photo initiator. In the case where a semiconductor wafer 101'
and a transparent substrate 102 are bonded together through a
spacer 104 formed on a substantially overall surface thereof to
obtain a bonded body 2000, and then the semiconductor wafer makes
one-fifth thickness, a warpage of the bonded body 2000 is 3,000
.mu.m or less. Further, it is preferred that the warpage of the
bonded body 2000 before the process thereof is 500 .mu.m or less,
and an increasing ratio of the warpage of the bonded body 2000
after the process thereof is 600% or less.
Inventors: |
Takahashi; Toyosei;
(Shinagawa-ku, JP) ; Kawata; Masakazu;
(Shinagawa-ku, JP) ; Yoneyama; Masahiro;
(Shinagawa-ku, JP) ; Dejima; Hirohisa;
(Shinagawa-ku, JP) ; Shiraishi; Fumihiro;
(Shinagawa-ku, JP) ; Sato; Toshihiro;
(Shinagawa-ku, JP) |
Family ID: |
43876230 |
Appl. No.: |
13/502002 |
Filed: |
October 14, 2010 |
PCT Filed: |
October 14, 2010 |
PCT NO: |
PCT/JP2010/068078 |
371 Date: |
April 13, 2012 |
Current U.S.
Class: |
428/64.1 ;
522/111 |
Current CPC
Class: |
H01L 2924/0002 20130101;
H01L 2924/15311 20130101; H01L 23/293 20130101; H01L 2924/0002
20130101; Y10T 428/21 20150115; H01L 23/3114 20130101; H01L 2924/00
20130101 |
Class at
Publication: |
428/64.1 ;
522/111 |
International
Class: |
B32B 3/02 20060101
B32B003/02; C09J 163/00 20060101 C09J163/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 15, 2009 |
JP |
2009-238757 |
Oct 15, 2009 |
JP |
2009-239756 |
Claims
1. A resin composition adapted to be used for providing a spacer
having a grid-like shape at a planar view thereof between a
semiconductor wafer and a transparent substrate, the resin
composition comprising: a constituent material containing an alkali
soluble resin, a thermosetting resin and a photo initiator, wherein
in the case where a semiconductor wafer having a substantially
circular shape, a diameter of 8 inches and a thickness of 725 .mu.m
and a transparent substrate having a substantially circular shape,
a diameter of 8 inches and a thickness of 350 .mu.m are bonded
together through a spacer formed on a substantially overall surface
of the semiconductor wafer or the transparent substrate using the
resin composition to thereby obtain a bonded body, a surface of the
semiconductor wafer opposite to the spacer is subjected to a
process for substantially uniformly grinding and/or polishing it so
that the semiconductor wafer has one-fifth thickness, and then the
bonded body is placed on a flat surface so that the transparent
substrate is located on the downside facing to the flat surface, a
maximal height of a space to be defined between the flat surface
and the transparent substrate, which corresponds to a warpage of
the bonded body, is 3,000 .mu.m or less.
2. The resin composition as claimed in claim 1, wherein the warpage
of the bonded body before the grinding and/or polishing process is
500 .mu.m or less, and an increasing ratio of the warpage of the
bonded body after the process thereof is 600% or less.
3. The resin composition as claimed in claim 1, wherein the alkali
soluble resin contains one or more selected from the group
consisting of an (epoxy)acrylate containing carboxyl groups, an
acryl resin containing carboxyl groups, an epoxy resin containing
carboxyl groups, a (meth)acryl-modified phenol resin and a polyamic
acid.
4. The resin composition as claimed in claim 1, wherein the alkali
soluble resin is a (meth)acryl-modified phenol resin.
5. The resin composition as claimed in claim 1, wherein the
thermosetting resin is an epoxy resin.
6. The resin composition as claimed in claim 1, wherein the
constituent material further contains a photo polymerizable
resin.
7. The resin composition as claimed in claim 1, wherein the spacer
is obtained by photo curing and thermal curing a layer formed of
the resin composition.
8. The resin composition as claimed in claim 1, wherein an elastic
modulus at 25.degree. C. of the spacer is in the range of 0.1 to 15
GPa.
9. The resin composition as claimed in claim 1, wherein a linear
expansion coefficient at 0 to 30.degree. C. of the spacer is in the
range of 3 to 150 ppm/.degree. C.
10. The resin composition as claimed in claim 1, wherein a residual
stress at 25.degree. C. of the spacer is in the range of 0.1 to 150
MPa.
11. The resin composition as claimed in claim 1, wherein a
thickness of the spacer is in the range of 5 to 500 .mu.m.
12. A semiconductor wafer bonding product having a substantially
circular shape, in which a semiconductor wafer, a spacer formed of
the resin composition defined by claim 1 so as to have a plurality
of air-gap portions provided in a grid pattern and a transparent
substrate are laminated in this order.
13. A semiconductor device obtained by dicing the semiconductor
wafer bonding product defined by claim 12.
Description
TECHNICAL FIELD
[0001] The present invention relates to a resin composition, a
semiconductor wafer bonding product and a semiconductor device.
RELATED ART
[0002] Semiconductor devices represented by a CMOS image sensor, a
CCD image sensor and the like are known. In general, such a
semiconductor device includes a semiconductor substrate provided
with a light receiving portion, a spacer provided on the
semiconductor substrate, and a transparent substrate bonded to the
semiconductor substrate via the spacer.
[0003] In order to improve productivity of such a semiconductor
device, a method in which the semiconductor device is manufactured
using a photosensitivity film is conceived (for example, Patent
document: JP-A 2008-91399).
[0004] For example, a plurality of semiconductor devices are
manufactured at the same time using such a photosensitivity film as
follows.
[0005] First, the photosensitivity film (spacer formation film) is
attached onto a semiconductor wafer provided with light receiving
portions so as to cover the light receiving portions of the
semiconductor wafer.
[0006] Next, the photosensitivity film is selectively irradiated
with light (exposed), and then developed. In this way, a grid-like
spacer (spacer substrate) is formed by selectively leaving the
photosensitivity film on an area of the semiconductor wafer
surrounding each light receiving portion.
[0007] Next, the semiconductor wafer on which the spacer is formed
faces a transparent substrate (transparent wafer) through the
spacer, and then is bonded to the transparent substrate, to thereby
obtain a semiconductor wafer bonding product in which the
semiconductor substrate and the transparent substrate are bonded
together through the spacer.
[0008] Next, by dicing the semiconductor wafer bonding product so
as to correspond to each light receiving portion provided on the
semiconductor wafer, a plurality of semiconductor devices are
manufactured at the same time.
[0009] As described above, the semiconductor device is manufactured
by dicing the semiconductor wafer bonding product in which the
semiconductor wafer and the transparent substrate are bonded
together through the spacer. On the other hand, recently, it is
required that a thickness of the semiconductor wafer is in the
range of about 100 to 600 .mu.m for downsizing or sliming the
semiconductor device, and that the thickness of the semiconductor
wafer is about 50 .mu.m for further downsizing or making the
semiconductor device thinner.
[0010] Further, in order to set the thickness of the semiconductor
wafer to such a small value, the semiconductor wafer is passed
through a back grinding step in which a surface thereof opposite to
the spacer is ground and/or polished. Practically, after this back
grinding step, the semiconductor wafer tends to warp or warpage of
the semiconductor wafer is likely to be increased.
[0011] Such a semiconductor wafer bonding product, in which the
warp occurs, is subjected to a back side process (e.g. TSV
process), a dicing process and the like after the back grinding
step.
[0012] The back side process includes, for example, a step of
laminating a photosensitive resist onto the semiconductor wafer
bonding product, a step of exposing the photosensitive resist and a
step of developing the photosensitive resist, and these steps are
successively carried out.
[0013] Therefore, in the case where the semiconductor wafer bonding
product is set to machines such as a laminator, an exposure machine
(stepper), a developing machine and a dicing saw, the semiconductor
wafer bonding product is received into a magazine case, and then
the magazine case is set to the machines. At this time, if the
warpage of the semiconductor wafer bonding product has become large
after the back grinding step, the semiconductor wafer bonding
product cannot be received into the magazine case and cannot be
properly set to the machines. This causes a fault that the
semiconductor wafer bonding product cannot be passed through the
above steps of the back side process.
[0014] Further, each machine transfers the semiconductor wafer
bonding product or secures the semiconductor wafer bonding product
onto a stage by sucking it. Therefore, even if the semiconductor
wafer bonding product can be received into the magazine case, in
the case where the warpage of the semiconductor wafer bonding
product has become large after the back grinding step, the
semiconductor wafer bonding product cannot be properly transferred
or secured by the sucking operation. This also causes a fault that
the semiconductor wafer bonding product cannot be subjected to the
back side process and the dicing process.
SUMMARY OF THE INVENTION
[0015] It is an object of the present invention to provide a resin
composition which can obtain a spacer capable of reducing a warpage
of a semiconductor wafer bonding product manufactured by bonding a
semiconductor wafer and a transparent substrate together through
the spacer, the semiconductor wafer bonding product in which a back
side of the semiconductor wafer is ground and/or polished, and to
provide a semiconductor wafer bonding product in which a warpage
thereof is reduced.
[0016] In order to achieve such an object, the present invention
includes the following features (1) to (12).
[0017] (1) A resin composition adapted to be used for providing a
spacer having a grid-like shape at a planar view thereof between a
semiconductor wafer and a transparent substrate, the resin
composition comprising:
[0018] a constituent material containing an alkali soluble resin, a
thermosetting resin and a photo initiator,
[0019] wherein in the case where a semiconductor wafer having a
substantially circular shape, a diameter of 8 inches and a
thickness of 725 .mu.m and a transparent substrate having a
substantially circular shape, a diameter of 8 inches and a
thickness of 350 .mu.m are bonded together through a spacer formed
on a substantially overall surface of the semiconductor wafer or
the transparent substrate using the resin composition to thereby
obtain a bonded body, a surface of the semiconductor wafer opposite
to the spacer is subjected to a process for substantially uniformly
grinding and/or polishing it so that the semiconductor wafer has
one-fifth thickness, and then the bonded body is placed on a flat
surface so that the transparent substrate is located on the
downside facing to the flat surface, a maximal height of a space to
be defined between the flat surface and the transparent substrate,
which corresponds to a warpage of the bonded body, is 3,000 .mu.m
or less.
[0020] (2) The resin composition according to the feature (1),
wherein the warpage of the bonded body before the grinding and/or
polishing process is 500 .mu.m or less, and an increasing ratio of
the warpage of the bonded body after the process thereof is 600% or
less.
[0021] (3) The resin composition according to the feature (1),
wherein the alkali soluble resin is a (meth)acryl-modified phenol
resin.
[0022] (4) The resin composition according to the feature (1),
wherein the thermosetting resin is an epoxy resin.
[0023] (5) The resin composition according to the feature (1),
wherein the constituent material further contains a photo
polymerizable resin.
[0024] (6) The resin composition according to the feature (1),
wherein the spacer is obtained by photo curing and thermal curing a
layer formed of the resin composition.
[0025] (7) The resin composition according to the feature (1),
wherein an elastic modulus at 25.degree. C. of the spacer is in the
range of 0.1 to 15 GPa.
[0026] (8) The resin composition according to the feature (1),
wherein a linear expansion coefficient at to 30.degree. C. of the
spacer is in the range of 3 to 150 ppm/.degree. C.
[0027] (9) The resin composition according to the feature (1),
wherein a residual stress at 25.degree. C. of the spacer is in the
range of 0.1 to 150 MPa.
[0028] (10) The resin composition according to the feature (1),
wherein a thickness of the spacer is in the range of 5 to 500
.mu.m.
[0029] (11) A semiconductor wafer bonding product having a
substantially circular shape, in which a semiconductor wafer, a
spacer formed of the resin composition according to the feature (1)
so as to have a plurality of air-gap portions provided in a grid
pattern and a transparent substrate are laminated in this
order.
[0030] (12) A semiconductor device obtained by dicing the
semiconductor wafer bonding product according to the feature
(11).
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIG. 1 is a sectional view showing one example of a
semiconductor device.
[0032] FIG. 2 is a flow chart showing one example of a method of
manufacturing the semiconductor device.
[0033] FIG. 3 is a flow chart showing the one example of the method
of manufacturing the semiconductor device, which is continued from
FIG. 2.
[0034] FIG. 4 is a top view showing a semiconductor wafer bonding
product of the present invention to be obtained in the course of
manufacturing the semiconductor device.
[0035] FIG. 5 is a longitudinal sectional view showing a warpage of
a bonded body.
MODE FOR CARRYING OUT THE INVENTION
[0036] Hereinafter, description will be made on a resin composition
and a semiconductor wafer bonding product of the present invention
based on a preferred embodiment shown in the accompanying
drawings.
[0037] <Semiconductor Device (Image Sensor)>
[0038] First, description will be made on a semiconductor device
(semiconductor element) manufactured using the semiconductor wafer
bonding product of the present invention, prior to the description
of the resin composition and the semiconductor wafer bonding
product of the present invention.
[0039] FIG. 1 is a longitudinal sectional view showing one example
of the semiconductor device manufactured using the semiconductor
wafer bonding product of the present invention. In this regard, in
the following description, the upper side in FIG. 1 will be
referred to as "upper" and the lower side thereof will be referred
to as "lower".
[0040] As shown in FIG. 1, a semiconductor device (light receiving
device) 100 includes a base substrate 101, a transparent substrate
102 provided so as to face the base substrate 101, an individual
circuit 103 formed on the base substrate 101 and having a light
receiving portion, a spacer 104 provided along an edge portion of
the individual circuit 103 having the light receiving portion, and
solder bumps 106 each formed on a lower surface of the base
substrate 101.
[0041] The base substrate 101 is a semiconductor substrate on which
a circuit not shown in FIG. 1 (that is, an individual circuit
provided on a semiconductor wafer described below) is provided.
[0042] On the base substrate 101, the individual circuit 103 having
the light receiving portion is provided. For example, the
individual circuit 103 having the light receiving portion has a
structure in which a light receiving element and a microlens array
are stacked on the base substrate 101 in this order.
[0043] The transparent substrate 102 is provided so as to face the
base substrate 101 and has a planar size substantially equal to a
planar size of the base substrate 101. Examples of the transparent
substrate 102 include an acryl resin substrate, a polyethylene
terephthalate resin (PET) substrate, a glass substrate and the
like.
[0044] The spacer 104 is directly bonded to both the microlens
array of the individual circuit 103 having the light receiving
portion and the transparent substrate 102 along edge portions
thereof. In this way, the base substrate 101 and the transparent
substrate 102 are bonded together through the spacer 104. Further,
the spacer 104 forms (defines) an air-gap portion 105 between the
individual circuit 103 having the light receiving portion
(microlens array) and the transparent substrate 102.
[0045] This spacer 104 is provided along the edge portion of the
individual circuit 103 having the light receiving portion so as to
surround a central area thereof. Therefore, an area of the
individual circuit 103 having the light receiving portion
surrounded by the spacer 104 can substantially function as a light
receiving portion.
[0046] In this regard, it is to be noted that examples of the light
receiving element of the individual circuit 103 having the light
receiving portion include CCD (Charge Coupled Device), a CMOS
(Complementary Metal Oxide Semiconductor) image sensor and the
like. In the light receiving element, light received by the
individual circuit 103 having the light receiving portion is
changed to electrical signals.
[0047] The solder bumps 106 have conductivity and are electrically
connected to a circuit provided on the base substrate 101 at the
lower surface and an inside thereof. This makes it possible for the
electrical signals changed from the light by the individual circuit
103 having the light receiving portion to be transmitted to the
solder bumps 106.
[0048] For example, such a semiconductor device 100 can be
manufactured as follows.
[0049] FIGS. 2 and 3 are longitudinal sectional views each showing
a method of manufacturing the semiconductor device. In this regard,
in the following description, the upper side in each of FIGS. 2 and
3 will be referred to as "upper" and the lower side thereof will be
referred to as "lower".
[0050] [1] First, prepared is a semiconductor wafer 101' on which
the individual circuits 103 having the light receiving portions are
provided and a plurality of individual circuits (not shown) each
corresponding to one semiconductor device 100 are formed.
[0051] In this embodiment, as shown in FIG. 2(a), the individual
circuit 103 having the light receiving portion is integrally formed
with the individual circuit provided on the semiconductor wafer
101'.
[0052] [2] Next, on a side of an upper surface of the semiconductor
wafer 101', that is, on a side of the semiconductor wafer 101'
where the individual circuits 103 having the light receiving
portions are provided, a spacer formation layer 12 having a bonding
property is formed.
[0053] Examples of a method of forming this spacer formation layer
12 include, but not are limited to, I: a method in which the spacer
formation layer 12 formed on a support base (film) 11 is
transferred on the semiconductor wafer 101', II: a method in which
a varnish (liquid material) containing a constituent material of
the spacer formation layer 12 is coated onto the semiconductor
wafer 101', and then dried to obtain the spacer formation layer 12,
III: a method in which the varnish containing the constituent
material of the spacer formation layer 12 is directly drawn onto
the semiconductor wafer 101', and the like.
[0054] Among these methods, it is preferable to use the method "I".
In the method "I", by exposing the spacer formation layer 12
through the support base 11, it is possible to effectively prevent
dust or the like from involuntarily adhering to the spacer
formation layer 12.
[0055] Hereinbelow, description will be made on a case that the
spacer formation layer 12 is formed onto the semiconductor wafer
101' using the method "I" as an example.
[0056] [2-1] First, as shown in FIG. 2(b), prepared is a spacer
formation film 1 in which the spacer formation layer 12 is provided
on the support base 11.
[0057] In the present invention, the spacer formation layer 12
contains an alkali soluble resin, a thermosetting resin and a photo
initiator. Such a spacer formation layer 12 has three properties
including a photo curable property that a region irradiated with
light is cured, an alkali developing property that a region not
irradiated with the light is dissolved by an alkali solution, and a
thermal curable property that the region irradiated with the light
is further cured by being heated.
[0058] Description will be made on a constituent material of a
resin composition to be used for forming the spacer formation layer
12 in detail below.
[0059] The support base (film) 11 is a sheet-like base and has a
function for supporting the spacer formation layer 12.
[0060] In the case where the spacer formation layer is irradiated
with the light through the support base 11 as described below (that
is, an exposure step [4] is carried out), this support base 11 is
formed of a material having optical transparency. By exposing the
spacer formation layer 12 through the support base 11 having such a
structure, it is possible to reliably expose the spacer formation
layer 12, while effectively preventing dust or the like from
involuntarily adhering to the spacer formation layer 12 during the
manufacture of the semiconductor device 100.
[0061] Examples of a constituent material of such a support base 11
include polyethylene terephthalate (PET), polypropylene (PP),
polyethylene (PE) and the like. Among them, it is preferable to use
the polyethylene terephthalate (PET) from the viewpoint that the
support base 11 can exhibit both optical transparency and rupture
strength in excellent balance.
[0062] In this regard, for example, such a spacer formation film 1
can be obtained by dissolving the alkali soluble resin, the
thermosetting resin and the photo initiator, when necessary, other
components such as a photo polymerizable resin into a solvent to
prepare a material for forming the spacer formation layer (liquid
material), and then applying the liquid material onto the support
base 11 and drying the liquid material due to removal of the
solvent thereof at a predetermined temperature.
[0063] Here, the solvent to be used is not limited to a specific
kind. As the solvent, a solvent inert with respect to the
constituent material of the spacer formation layer (resin
composition) 12 is preferably used.
[0064] Specifically, examples of such a solvent include: ketones
such as acetone, methyl ethyl ketone, methyl isobutyl ketone, DIBK
(diisobutyl ketone), cyclohexanone and DAA (diacetone alcohol);
esters such as ethyl acetate and butyl acetate; aromatic
hydrocarbons such as benzene, xylene and toluene; alcohols such as
methyl alcohol, ethyl alcohol, isopropyl alcohol and n-butyl
alcohol; cellosolve based solvents such as methyl cellosolve, ethyl
cellosolve, butyl cellosolve, methyl cellosolve acetate, ethyl
cellosolve acetate, BCSA (butyl cellosolve acetate); NMP
(N-methyl-2-pyrolidone); THF (tetrahydrofuran); DMF (dimethyl
formamide); DMAC (dimethyl acetamide); DBE (dibasic acid ester);
EEP (ethyl 3-ethoxypropionate); DMC (dimethyl carbonate); and the
like.
[0065] Further, an amount of the solvent contained in the material
for forming the spacer formation layer (liquid material) is
preferably set to a value falling within such a range that an
amount of the solid components mixed in the solvent (namely, the
constituent material of the spacer formation layer 12) becomes
about 10 to 60 wt %.
[0066] [2-2] Next, as shown in FIG. 2(c), the spacer formation
layer 12 (bonding surface) of the spacer formation film 1 is
attached to a surface of the semiconductor wafer 101' on which the
individual circuits 103 having the light receiving portions are
provided (this step is referred to as a laminating step). In this
way, the spacer formation layer 12 is attached to the semiconductor
wafer 101' so as to be located at the side of the individual
circuits 103 having the light receiving portions in a state that it
keeps the support base 11 at a side opposite to the semiconductor
wafer 101'.
[0067] In this regard, for example, the attachment of the spacer
formation layer 12 to the surface (upper surface) of the
semiconductor wafer 101' on which the side of the individual
circuits 103 having the light receiving portions are provided can
be carried out as follows.
[0068] First, the spacer formation film 1 is aligned with respect
to the semiconductor wafer 101', and then one end side of a lower
surface of the spacer formation film 1 is contacted to one end side
of an upper surface of the semiconductor wafer 101'.
[0069] Next, in this state, the spacer formation film 1 and the
semiconductor wafer 101' are set to a bonding machine so that a
portion where the lower surface of the spacer formation film 1 is
contacted to the upper surface of the semiconductor wafer 101' is
nipped by a pair of rollers. In this way, the spacer formation film
1 and the semiconductor wafer 101' are compressed.
[0070] Next, the pair of rollers are moved from the one sides of
the spacer formation film 1 and the semiconductor wafer 101' to the
other sides thereof. At this time, in a portion of the spacer
formation film and the semiconductor wafer 101' nipped by the
rollers, the spacer formation layer 12 is sequentially bonded to
the individual circuits 103 having the light receiving portions. As
a result, the spacer formation layer 12 is attached (bonded) to the
semiconductor wafer 101'.
[0071] A compression pressure when the spacer formation film 1 and
the semiconductor wafer 101' are nipped by the rollers is not
limited to a specific value, but is preferably in the range of
about 0.1 to 10 kgf/cm.sup.2, and more preferably in the range of
about 0.2 to 5 kgf/cm.sup.2. This makes it possible for the spacer
formation layer 12 to be reliably bonded to the individual circuits
103 having the light receiving portions.
[0072] A speed of moving each roller is not limited to a specific
value, but is preferably in the range of about 0.1 to 1.0 m/min,
and more preferably in the range of about 0.2 to 0.6 m/min.
[0073] Further, a heating means such as a heater is provided in
each roller. Therefore, the portion of the spacer formation film 1
and the semiconductor wafer 101' nipped by the rollers is heated. A
heat temperature is preferably in the range of about 0 to
120.degree. C., and more preferably in the range of about 40 to
100.degree. C.
[0074] [3] Next, the spacer formation layer 12 formed on the
semiconductor wafer 101' is heated (this step is referred to as a
PLB (Post Lamination Baking) step).
[0075] At this time, the spacer formation layer 12 positioned on
steps of the individual circuits 103 having the light receiving
portions can be fluid flowed. This makes it possible to make a
surface of the spacer formation layer 12 more smooth.
[0076] A temperature of heating the spacer formation layer 12 is
preferably in the range of about 20 to 120.degree. C., and more
preferably in the range of about 30 to 100.degree. C.
[0077] Further, a time of heating the spacer formation layer 12 is
preferably in the range of about 0.1 to 10 minutes, and more
preferably in the range of about 2 to 7 minutes.
[0078] [4] Next, a region of the spacer formation layer 12 to be
brought into the spacer 104 is exposed by being irradiated with
light (this step is referred to as an exposure step).
[0079] In this way, in the spacer formation layer 12, the region to
be brought into the spacer 104 is selectively photo
cross-linked.
[0080] For example, the light irradiation to the region of the
spacer formation layer 12 to be brought into the spacer 104 is
carried out, as shown in FIG. 2(d), by irradiating the region with
the light through a mask 20 having an opening portion 201
corresponding to the region.
[0081] In this regard, in this embodiment, the exposure of the
spacer formation layer 12 is carried out through the support base
11. By exposing the spacer formation layer 12 in this way, it is
possible to reliably expose the spacer formation layer 12, while
effectively preventing dust or the like from involuntarily adhering
to the spacer formation layer 12.
[0082] Further, in the case where the spacer formation layer 12 is
exposed without the support base 11, there is a fear that flatness
of the surface of the spacer formation layer 12 is lowered due to
adhesion of the mask 20 thereto or there is a fear that a part of
the previous spacer formation layer 12 adhering to the mask 20 is
transferred (re-adheres) to the spacer formation layer 12 provided
on the semiconductor wafer 101' to be subsequently exposed.
[0083] However, by exposing the spacer formation layer 12 through
the support base 11, it is also possible to obtain an advantage of
effectively preventing the above problems.
[0084] A wavelength of the light, with which the spacer formation
layer 12 is irradiated, is preferably in the range of about 150 to
700 nm, and more preferably in the range of about 150 to 450
nm.
[0085] Further, an integrated dose of the light, with which the
spacer formation layer 12 is irradiated, is preferably in the range
of about 200 to 3,000 mJ/cm.sup.2, and more preferably in the range
of about 300 to 2,500 mJ/cm.sup.2.
[0086] [5] Next, the spacer formation layer 12 after the exposure
is heated (this step is referred to as a PEB (Post Exposure Baking)
step).
[0087] This makes it possible to more firmly cure the region of the
spacer formation layer 12 to be brought into the spacer 104, and to
more strongly bond the region of the spacer formation layer 12 to
be brought into the spacer 104 to the individual circuits 103
having the light receiving portions. Further, this also makes it
possible to a reduce residual stress of the spacer formation layer
12.
[0088] A temperature of heating the spacer formation layer 12 is
preferably in the range of about 30 to 120.degree. C., and more
preferably in the range of about 30 to 100.degree. C.
[0089] Further, a time of heating the spacer formation layer 12 is
preferably in the range of about 1 to 10 minutes, and more
preferably in the range of about 2 to 7 minutes.
[0090] [6] Next, the spacer formation layer 12 after the exposure
is developed using an alkali solution (this step is referred to as
a developing step).
[0091] By doing so, as shown in FIG. 2(e), a region of the spacer
formation layer 12 not exposed is removed (etched), to thereby
obtain a spacer 104 having air-gap portions 105 formed from the
removed region. In other words, it is possible to obtain a spacer
(spacer substrate) 104 formed from the exposed region.
[0092] In this regard, since the resin composition of the present
invention has high sensitivity with respect to the light to be used
in the step [4], it has an excellent patterning property. For this
reason, in this step, it is possible to form a spacer 104 having a
designed shape.
[0093] Further, in this embodiment, since the support base 11 is
provided on the spacer formation layer 12, the support base 11 is
removed from the spacer formation layer 12 prior to the development
of the spacer formation layer 12.
[0094] pH of the alkali solution to be used is preferably 9.5 or
more, and more preferably in the range of about 11.0 to 14.0. This
makes it possible to effectively remove the spacer formation layer
12.
[0095] Examples of such an alkali solution include an aqueous
solution of an alkali metal hydroxide such as NaOH or KOH, an
aqueous solution of an alkali earth metal hydroxide such as
Mg(OH).sub.2, an aqueous solution of tetramethyl ammonium
hydroxide, an amide-type organic solvent such as N,N-dimethyl
formamide (DMF) or N,N-dimethyl acetoamide (DMA) and the like.
These alkali solutions are used alone or two or more of them are
used in combination.
[0096] [7] Next, as shown in FIG. 3(a), a transparent substrate 102
is attached to the spacer 104 formed on the semiconductor wafer
101'. Namely, the transparent substrate 102 is attached to the
semiconductor wafer 101' through the spacer 104 (this step is
referred to as an attaching step).
[0097] In this regard, for example, the transparent substrate 102
can be attached to the semiconductor wafer 101' using the same
method as described in the above step [2-2] in which the spacer
formation film 1 is attached to the semiconductor wafer 101'.
[0098] [8] Next, the spacer 104 is thermal cured by heating the
semiconductor wafer 101' and the transparent substrate 102 in the
state that they are bonded together through the spacer 104 (this
step is referred to as a thermal curing step).
[0099] By doing so, the spacer 104 and the transparent substrate
102 are physically bonded together. As a result, it is possible to
obtain a semiconductor wafer bonding product 1000 in which the
semiconductor wafer 101' and the transparent substrate 102 are
bonded together through the spacer 104, that is, a semiconductor
wafer bonding product 1000 having the plurality of air-gap portions
105 between the semiconductor wafer 101' and the transparent
substrate 102 (see FIG. 4).
[0100] A temperature of heating the spacer 104 is preferably in the
range of about 80 to 180.degree. C., and more preferably in the
range of about 110 to 160.degree. C. By heating the spacer 104
within the above temperature range, it is possible to make a shape
of the formed spacer 104 appropriate.
[0101] [9] Next, as shown in FIG. 3(b), a lower surface (back side)
111 of the semiconductor wafer 101' opposite to the transparent
substrate 102' bonded thereto is subjected to at least one of
processes such as grinding and polishing (this step is referred to
as a back grinding step).
[0102] This lower surface 111 is ground using, for example, a
grinding disk of a grinding machine (grinder).
[0103] By the process of such a surface 111, a thickness of the
semiconductor wafer 101' is generally set to about 100 to 600 .mu.m
depending on an electronic device in which the semiconductor device
100 is used. In the case where the semiconductor device 100 is used
in an electronic device having a smaller size, the thickness of the
semiconductor wafer 101' is set to about 50 .mu.m.
[0104] If the thickness of the semiconductor wafer 101' makes small
in this way, warp which would occur in the semiconductor wafer
bonding product 1000 becomes large as described above. This causes
the following problems during a back side processing step [10] and
a dicing step [11] which are post-steps.
[0105] Namely, the semiconductor wafer bonding product 1000 is
passed through the back side processing step [10] and the dicing
step [11] after this step [9].
[0106] The back side processing step [10] includes, for example, a
process of laminating a photosensitive resist onto the
semiconductor wafer bonding product 1000, a process of exposing the
photosensitive resist and a process of developing the
photosensitive resist.
[0107] Therefore, in the case where the semiconductor wafer bonding
product 1000 is set to machines such as a laminator, an exposure
machine (stepper), a developing machine and a dicing saw, the
semiconductor wafer bonding product 1000 is received into a
magazine case, and then the magazine case is set to the machines.
At this time, if warpage of the semiconductor wafer bonding product
1000 has become large after the step [9], the semiconductor wafer
bonding product 1000 can be not received into the magazine case, to
thereby be not set to the machines. This causes a fault that the
semiconductor wafer bonding product 1000 cannot be passed through
the above post-steps.
[0108] Further, each machine transfers the semiconductor wafer
bonding product 1000 or secures the semiconductor wafer bonding
product 1000 onto a stage by sucking it. Therefore, even if the
semiconductor wafer bonding product 1000 can be received into the
magazine case, in the case where the warpage of the semiconductor
wafer bonding product 1000 has become large by being back ground,
the semiconductor wafer bonding product 1000 cannot be transferred
or secured by being sucked. This also causes a fault that the back
side processing step [10] and the dicing step [11] cannot be
carried out.
[0109] In order to solve the above problems, in the present
invention, a bonded body 2000 for identifying (measuring) a warpage
of the semiconductor wafer bonding product is prepared, a warpage
of the bonded body 2000 becomes 3,000 .mu.m or less.
[0110] Here, in the present invention, the bonded body 2000
includes: a semiconductor wafer 101' having a substantially
circular shape, a diameter of 8 inches and a thickness of 725
.mu.m; a transparent substrate 102 having a substantially circular
shape, a diameter of 8 inches and a thickness of 350 .mu.m; and a
spacer 104 through which the semiconductor wafer 101' and the
transparent substrate 102 are bonded together, the spacer 104
formed on a substantially overall surface of the semiconductor
wafer 101' or the transparent substrate 102 (see FIG. 5).
[0111] Further, by subjecting the semiconductor wafer 101' to a
process for substantially uniformly grinding and/or polishing a
lower surface 111 thereof, a thickness of the semiconductor wafer
101' is set to one-fifth.
[0112] Further, from a relationship among the semiconductor wafer
101', the transparent substrate 102 and the spacer 104 in a linear
expansion coefficient, an elastic modulus and the like, when the
bonded body 2000 is placed on a flat surface so that the
transparent substrate 102 is located on the downside as shown in
FIG. 5, a position of a central portion of transparent substrate
102 becomes higher than a position of an outer portion thereof, and
thus a space (gap) 112 is formed between the flat surface and a
surface of the transparent substrate 102.
[0113] In the present invention, a maximum height of the space 112
is defined as a warpage of the bonded body 2000.
[0114] If the warpage of such a bonded body 2000 is 3,000 .mu.m or
less, preferably 1,000 .mu.m or less, and more preferably 500 .mu.m
or less (excluding 0 .mu.m), it is possible to effectively suppress
or prevent the semiconductor wafer bonding product 1000 from being
not received into the machine for carrying out the below mentioned
back side processing step [10] or dicing step [11] or from being
broken by being hooked into the machine.
[0115] Further, in the present invention, it is preferred that a
warpage of the semiconductor wafer bonding product 1000 before a
lower surface 111 thereof is subjected to a process (grinding
and/or polishing) is small and an increasing rate of the warpage of
the semiconductor wafer bonding product 1000, which would occur by
being subjected to the process, is suppressed.
[0116] Specifically, the bonded body 2000 for identifying the
warpage of the semiconductor wafer bonding product is prepared,
when the surface of the semiconductor wafer 101' opposite to the
spacer 104 is subjected to a process for substantially uniformly
grinding and/or polishing it so that the semiconductor wafer 101'
has one-fifth thickness, it is preferred that the warpage of the
bonded body 2000 before the process of the semiconductor wafer 101'
is 5,000 .mu.m or less and that the increasing rate of the warpage
of the bonded body 2000 after the process of the semiconductor
wafer 101' is suppressed to 600% or less.
[0117] In this regard, in the present invention, in the case where
the warpage of the bonded body 2000 before the grinding of the
lower surface 111 is defined as "A" and the warpage of the bonded
body 2000 after the grinding of the lower surface 111 is defined as
"B", the increasing rate of the warpage of the bonded body 2000 is
a value calculated by [(B-A)/A].times.100(%).
[0118] The warpage of the bonded body 2000 before the process
(grinding and/or polishing) thereof is preferably 500 .mu.m or
less, more preferably 400 .mu.m or less, and even more preferably
in the range of about 50 to 300 .mu.m. Further, when the
semiconductor wafer 101' is processed so as to have one-fifth
thickness, the increasing rate of the warpage of the bonded body
2000 becomes preferably 600% or less, more preferably 500% or less,
and even more preferably 400% or less (excluding 0%).
[0119] By satisfying such relationships, since the warpage of the
bonded body 2000 before the process thereof is reliably small and
the increasing rate of the warpage of the bonded body 2000 after
the process thereof is reliably suppressed, it is possible to
effectively suppress or prevent the semiconductor wafer bonding
product 1000 described below from being not received into the
machine for carrying out the below mentioned back side processing
step [10] or dicing step [11] or from being broken by being hooked
into the machine.
[0120] Namely, by setting the warpage of the bonded body 2000 for
identifying the warpage of the semiconductor wafer bonding product
to a value falling within such a range, the warpage of the
semiconductor wafer bonding product 1000 to be used as an actual
product becomes a problem-free magnitude when carrying out the back
side processing step [10] and the dicing step [11]. Therefore, it
is possible to reliably suppress or prevent problems which would
occur when the steps [10] and [11] are carried out.
[0121] As described above, in the present invention, the resin
composition to be used for forming a spacer 104 having a grid-like
shape at a planar view thereof is formed of the constituent
material containing the alkali soluble resin, the thermosetting
resin and the photo initiator, so that the warpage of the bonded
body 2000 is 3,000 .mu.m or less, and preferably so that the
warpage of the bonded body 2000 before the process thereof is 500
.mu.m or less and the increasing rate of the warpage of the bonded
body 2000 after the process thereof is 6000 or less.
[0122] In this regard, it the present invention, a thickness of the
spacer 104 of the bonded body 2000 is preferably in the range of
about 20 to 80 .mu.m, and more preferably about 50 .mu.m.
[0123] Further, as the transparent substrate 102, a substrate
having the same elastic modulus and linear expansion coefficient as
those of the semiconductor wafer 101' is appropriately selected.
Specifically, as the transparent substrate 102, a substrate
constituted from a silicon oxide-based material such as silica
glass (quartz glass) or silica (crystal) is appropriately used.
[0124] In the case of the bonded body 2000 in which the thickness
of the spacer 104 falls within the above range and the kind of the
constituent material of the transparent substrate 102 is selected,
in order to set so that the warpage thereof is 3,000 .mu.m or less,
and preferably so that the warpage before the process thereof is
500 .mu.m or less and the increasing rate of the warpage after the
process thereof is 600% or less, the constituent material of the
resin composition to be used for forming the spacer 104 is
adjusted.
[0125] As described above, the spacer formation layer 12
constituted from the resin composition containing the alkali
soluble resin, the thermosetting resin and the photo initiator has
I: the photo curable property that the region irradiated with the
light is cured, II: the alkali developing property that the region
not irradiated with the light is dissolved by the alkali solution
and III: the thermal curable property that the region irradiated
with the light is further cured by being heated, and IV: such a
spacer formation layer 12 can suppress the warpage of the bonded
body 2000 to 3,000 .mu.m or less in a reliable manner.
[0126] Here, as the constituent material of the resin composition,
preferably selected is a material which can appropriately exhibit
the above properties "I" to "III" and can make the warpage of the
bonded body 2000 described as "IV" small. Further, as the
constituent material of the resin composition, more preferably
selected is a material which can adjust the warpage of the bonded
body 2000 before the process thereof to 500 .mu.m or less and
adjust the increasing rate of the warpage of the bonded body 2000
after the process thereof to 600% or less.
[0127] Hereinbelow, description will be made on each of components
of the resin composition in detail.
[0128] (Alkali Soluble Resin)
[0129] The resin composition constituting the spacer formation
layer 12 (that is, the resin composition of the present invention)
contains the alkali soluble resin. This makes it possible for the
spacer formation layer 12 to exhibit the alkali developing
property.
[0130] Examples of the alkali soluble resin include: a phenol resin
containing phenolic hydroxyl groups such as a cresol-type resin, a
phenol-type resin, a bisphenol A-type resin, a bisphenol F-type
resin, a catechol-type resin or a pyrogallol-type resin; a phenol
aralkyl resin; a hydroxystyrene resin; an (meth)acrylate resin such
as an acryl-based resin obtained by polymerizing (meth)acryl-type
monomers each containing a hydroxyl group or a carboxyl group, an
epoxy acrylate containing hydroxyl groups or carboxyl groups or an
urethane acrylate; a cyclic olefin-based resin containing hydroxyl
groups, carboxyl groups or the like; a polyamide-based resin; and
the like. These alkali soluble resins may be used alone or in
combination of two or more of them.
[0131] In this regard, concrete examples of the polyamide-based
resin include: a resin containing at least one of a polybenzoxazole
structure and a polyimide structure, and hydroxyl groups, carboxyl
groups, ether groups or ester groups in a main chain or branch
chains thereof; a resin containing a polybenzoxazole precursor
structure; a resin containing a polyimide precursor structure; a
resin containing a polyamide acid ester structure; and the
like.
[0132] Examples of the (meth)acryl-type monomers to be used for
synthesizing the acryl-based resin obtained by polymerizing
(meth)acryl-type monomers each containing a hydroxyl group or a
carboxyl group include 2-hydroxyethyl (meth)acrylate containing a
hydroxyl group, (meth)acrylic acid containing a carboxyl group and
the like. These monomers may be radical polymerized alone, but may
be co-polymerized with a monomer having a double bond such as a
(meth)acrylate monomer (e.g., methyl (meth)acrylate, ethyl
(meth)acrylate, isopropyl (meth)acrylate or n-butyl (meth)acrylate,
acrylonitrile containing a nitrile group, styrene, divinyl benzene
or butadiene.
[0133] Among these alkali soluble resins, it is preferable to use
an alkali soluble resin containing both alkali soluble groups,
which contribute to the alkali developing, and double bonds.
[0134] Examples of the alkali soluble groups include a hydroxyl
group, a carboxyl group and the like. The alkali soluble groups can
also contribute to a thermal curing reaction in addition to the
alkali developing. Further, since the alkali soluble resin contains
the double bonds, it also can contribute to a photo curing
reaction.
[0135] Examples of such a resin containing alkali soluble groups
and double bonds include a curable resin which can be cured by both
light and heat. Concrete examples of the curable resin include a
thermosetting resin containing photo reaction groups such as an
acryloyl group, a methacryloyl group and a vinyl group; a photo
curable resin containing thermal reaction groups such as a phenolic
hydroxyl group, an alcoholic hydroxyl group, a carboxyl group and
an anhydride group; and the like.
[0136] In this regard, it is to be noted that the photo curable
resin containing thermal reaction groups may further have other
thermal reaction groups such as an epoxy group, an amino group and
a cyanate group. Concrete examples of the photo curable resin
having such a chemical structure include a (meth)acryl-modified
phenol resin, a (meth)acryl-modified bisphenol A-type resin, an
acryl acid polymer containing (meth)acryloyl groups, an
(epoxy)acrylate containing carboxyl groups, a polybenzooxazole
precursor resin containing double bonds, a polyimide precursor
resin containing double bonds and the like. Further, the photo
curable resin may be a thermoplastic resin such as an acryl resin
containing carboxyl groups.
[0137] Among the above resins each containing alkali soluble groups
and double bonds (that is, the curable resins which can be cured by
both light and heat), it is preferable to use the
(meth)acryl-modified phenol resin or the (meth)acryl-modified
bisphenol A-type resin.
[0138] By using the (meth)acryl-modified phenol resin or the
(meth)acryl-modified bisphenol A-type resin, since each resin
contains the alkali soluble groups, when the resin which has not
reacted is removed during a developing treatment, an alkali
solution having less adverse effect on environment can be used as a
developer instead of an organic solvent which is normally used.
Further, since each resin contains the double bonds, these double
bonds contribute to the curing reaction. As a result, it is
possible to improve heat resistance of the resin composition.
[0139] Furthermore, by using the (meth)acryl-modified phenol resin
or the (meth)acryl-modified bisphenol A-type resin, it is possible
to reliably reduce the warpage of the bonded body 2000 before the
process (grinding and/or polishing) of the semiconductor wafer 101'
and to effectively suppress the increasing rate of the warpage of
the bonded body 2000 after the process (grinding and/or polishing)
of the semiconductor wafer 101'. From the viewpoint of such a fact,
it is also preferable to use the (meth)acryl-modified phenol resin
or the (meth)acryl-modified bisphenol A-type resin.
[0140] Examples of the (meth)acryl-modified phenol resin or the
(meth)acryl-modified bisphenol A-type resin include a
(meth)acryloyl-modified bisphenol resin or a (meth)acryl-modified
bisphenol A-type resin obtained by reacting hydroxyl groups
contained in bisphenols or bisphenols with epoxy groups of
compounds containing the epoxy groups and (meth)acryloyl
groups.
[0141] Concretely, examples of such a (meth)acryl-modified
bisphenol A-type resin include a resin represented by the following
chemical formula I.
##STR00001##
[0142] Further, as another resin containing alkali soluble groups
and double bonds, exemplified is a compound introducing a dibasic
acid into a molecular chain of a (meth)acryloyl-modified epoxy
resin in which (meth) acryloyl groups are bonded to both ends of an
epoxy resin, the compound obtained by bonding one of carboxyl
groups of the dibasic acid to one hydroxyl group of the molecular
chain of the (meth)acryloyl-modified epoxy resin via an ester bond.
In this regard, it is to be noted that this compound has one or
more repeating units of the epoxy resin and one or more dibasic
acids introduced into the molecular chain.
[0143] Such a compound can be synthesized by reacting epoxy groups
existing both ends of an epoxy resin obtained by polymerizing
epichlorohydrin and polyalcohol with (meth)acrylic acid to obtain a
(meth)acryloyl-modified epoxy resin in which acryloyl groups are
introduced into both the ends of the epoxy resin, and then reacting
hydroxyl groups of a molecular chain of the (meth)acryloyl-modified
epoxy resin with an anhydride of a dibasic acid to form an ester
bond together with one of carboxyl groups of the dibasic acid.
[0144] Here, in the case of using the thermosetting resin
containing photo reaction groups, a modified ratio (substitutional
ratio) of the photo reaction groups is not limited to a specific
value, but is preferably in the range of about 20 to 80%, and more
preferably about 30 to 70% with respect to total reaction groups of
the resin containing alkali soluble groups and double bonds. If the
modified ratio of the photo reaction groups falls within the above
range, it is possible to provide a resin composition having an
excellent developing property.
[0145] On the other hand, in the case of using the photo curable
resin containing thermal reaction groups, a modified ratio
(substitutional ratio) of the thermal reaction groups is not
limited to a specific value, but is preferably in the range of
about 20 to 80%, and more preferably in the range of about 30 to
70% with respect to total reaction groups of the resin containing
alkali soluble groups and double bonds. If the modified ratio of
the thermal reaction groups falls within the above range, it is
possible to provide a resin composition having an excellent
developing property.
[0146] Further, in the case where the resin having alkali soluble
groups and double bonds is used as the alkali soluble resin, a
weight-average molecular weight of the resin is not limited to a
specific value, but is preferably 30,000 or less, and more
preferably in the range of about 5,000 to 15,000. If the
weight-average molecular weight falls within the above range, it is
possible to further improve a film forming property of the resin
composition in forming the spacer formation layer onto a film.
[0147] Here, the weight-average molecular weight of the alkali
soluble rein can be measured using, for example, a gel permeation
chromatographic method (GPC). That is, according to such a method,
the weight-average molecular weight can be calculated based on a
calibration curve which has been, in advance, made using styrene
standard substances. In this regard, it is to be noted that the
measurement is carried out using tetrahydrofuran (THF) as a
measurement solvent at a measurement temperature of 40.degree.
C.
[0148] Further, an amount of the alkali soluble resin contained in
the resin composition is not limited to a specific value, but is
preferably in the range of about 15 to 50 wt %, and more preferably
in the range of about 20 to 40 wt % with respect to a total amount
of the resin composition. In this regard, in the case where the
resin composition contains a filler described below, the amount of
the alkali soluble resin may be preferably in the range of about 10
to 80 wt %, and more preferably in the range of about 15 to 70 wt %
with respect to resin components contained in the resin composition
(total components excluding the filler).
[0149] If the amount of the alkali soluble resin is less than the
above lower limit value, there is a case that an effect of
improving compatibility with other components (e.g., the photo
curable resin and the thermosetting resin each described below)
contained in the resin composition is lowered. On the other hand,
if the amount of the alkali soluble resin exceeds the upper limit
value, there is a fear that patterning resolution of the spacer
formed by a photo lithography technique is lowered.
[0150] In other words, if the amount of the alkali soluble resin
falls within the above range, it is possible for the resin
composition patterned by the photo lithography technique to more
reliably exhibit the thermal bonding property.
[0151] (Thermosetting Resin)
[0152] Further, the resin composition constituting the spacer
formation layer 12 contains the thermosetting resin. This makes it
possible for the spacer formation layer 12 to exhibit a bonding
property due to curing thereof, even after it has been exposed and
developed. Namely, after the spacer formation layer 12 has been
bonded to the semiconductor wafer, and exposed and developed, the
transparent substrate 10 can be bonded to the spacer formation
layer 12 by thermal bonding.
[0153] In this regard, in the case where the curable resin which
can be cured by heat is used as the above alkali soluble resin, a
resin other than the curable resin is selected as the thermosetting
resin.
[0154] Specifically, examples of the thermosetting resin include: a
novolac-type phenol resin such as a phenol novolac resin, a cresol
novolac resin and a bisphenol A novolac resin; a phenol resin such
as a resol phenol resin; an epoxy resin such as a bisphenol-type
epoxy resin (e.g., a bisphenol A epoxy resin, a bisphenol F epoxy
resin), a novlolac-type epoxy resin (e.g., a novolac epoxy resin, a
cresol novolac epoxy resin), a biphenyl-type epoxy resin, a
stilbene-type epoxy resin, a triphenol methane-type epoxy resin, an
alkyl-modified triphenol methane-type epoxy resin, a triazine
chemical structure-containing epoxy resin, a
dicyclopentadiene-modified phenol-type epoxy resin and an epoxy
resin having naphthalene skeletons; an urea resin; a resin having
triazine rings such as a melamine resin; an unsaturated polyester
resin; a bismaleimide resin; a polyurethane resin; a diallyl
phthalate resin; a silicone resin; a resin having benzooxazine
rings; a cyanate ester resin; an epoxy-modified siloxane; and the
like. These thermosetting resins may be used singly or in
combination of two or more of them.
[0155] Among the thermosetting resins, it is preferable to use the
epoxy resin. This makes it possible to improve heat resistance of
the spacer formation layer and adhesion thereof to the transparent
substrate 102. Further, this makes it possible to reliably reduce
the warpage of the bonded body 2000. Furthermore, this also makes
it possible to reliably reduce the warpage of the bonded body 2000
before the process (grinding and/or polishing) of the semiconductor
wafer 101' and to effectively suppress the increasing rate of the
warpage of the bonded body 2000 after the process (grinding and/or
polishing) of the semiconductor wafer 101'.
[0156] Furthermore, in the case of using the epoxy resin as the
thermosetting resin, it is preferred that an epoxy resin in a solid
state at room temperature (in particular, bisphenol-type epoxy
resin) and an epoxy resin in a liquid state at room temperature (in
particular, silicone-modified epoxy resin in a liquid state at room
temperature) are used in combination as the epoxy resin. This makes
it possible to obtain a spacer formation layer 12 having excellent
flexibility and resolution, while maintaining heat resistance
thereof.
[0157] An amount of the thermosetting resin contained in the resin
composition is not limited to a specific value, but preferably in
the range of about 10 to 40 wt %, and more preferably in the range
of about 15 to 35 wt % with respect to the total amount of the
resin composition. If the amount of the thermosetting resin is less
than the above lower limit value, there is a case that an effect of
improving the heat resistance of the spacer formation layer 12
after being thermally cured is lowered. On the other hand, if the
amount of the thermosetting resin exceeds the above upper limit
value, there is a case that an effect of improving toughness of the
spacer formation layer 12 after being thermally cured is
lowered.
[0158] Further, in the case of using the above epoxy resin, it is
preferred that the thermosetting resin further contains the phenol
novolac resin in addition to the epoxy resin. Addition of the
phenol novolac resin makes it possible to improve the resolution of
the spacer formation layer 12. Furthermore, in the case where the
resin composition contains both the epoxy resin and the phenol
novolac resin as the thermosetting resin, it is also possible to
obtain an advantage that the thermal curable property of the epoxy
resin can be further improved, to thereby make the strength of the
spacer 104 to be formed higher.
[0159] (Photo Initiator)
[0160] The resin composition constituting the spacer formation
layer 12 further contains the photo initiator. This makes it
possible to more effectively pattern the spacer formation layer 12
due to photo polymerization thereof.
[0161] Examples of the photo initiator include benzophenone,
acetophenone, benzoin, benzoin isobutyl ether, benzoin methyl
benzoate, benzoin benzoic acid, benzoin methyl ether, benzyl phenyl
sulfide, benzyl, dibenzyl, diacetyl and the like.
[0162] An amount of the photo initiator contained in the resin
composition is not limited to a specific value, but is preferably
in the range of about 0.5 to 5 wt %, and more preferably in the
range of about 0.8 to 3.0 wt % with respect to the total amount of
the resin composition. If the amount of the photo initiator is less
than the above lower limit value, there is a fear that an effect of
starting the photo polymerization of the spacer formation layer 12
cannot be sufficiently obtained. On the other hand, if the amount
of the photo initiator exceeds the above upper limit value,
reactivity of the spacer formation layer 12 is extremely improved,
and therefore there is a fear that storage stability or resolution
thereof is lowered.
[0163] (Photo Polymerizable Resin)
[0164] It is preferred that the resin composition constituting the
spacer formation layer 12 also contains a photo polymerizable resin
in addition to the above components. If the resin composition
contains the photo polymerizable resin together with the above
mentioned alkali soluble resin, it is possible to further improve a
patterning property of the spacer formation layer 12 to be
obtained.
[0165] In this regard, in the case where the curable resin which
can be cured by light is used as the above alkali soluble resin, a
resin other than the curable resin is selected as the photo
polymerizable resin.
[0166] Examples of the photo polymerizable resin include: but are
not limited to, an unsaturated polyester; a (meth)acryl-based
compound such as a (meth)acryl-based monomer and a
(meth)acryl-based oligomer each containing one or more acryloyl
groups or one or more methacryloyl groups in one molecule thereof;
a vinyl-based compound such as styrene; and the like. These photo
polymerizable resins may be used alone or in combination of two or
more of them.
[0167] Among them, an ultraviolet curable resin containing the
(meth)acryl-based compound as a major component thereof is
preferable. This is because a curing rate of the (meth)acryl-based
compound is fast when being exposed (irradiated) with light, and
therefore it is possible to appropriately pattern the resin with a
relative small exposure amount.
[0168] Examples of the (meth)acryl-based compound include a monomer
of an acrylic acid ester or methacrylic acid ester, and the like.
Concretely, examples of the monomer include: a difunctional
(meth)acrylate such as ethylene glycol di(meth)acrylate,
1,6-hexanediol di(meth)acrylate, glycerin di(meth)acrylate and
1,10-decanediol di(meth)acrylate; a trifunctional (meth)acrylate
such as trimethylol propane tri(meth)acrylate and pentaerythritol
tri(meth)acrylate; a tetrafunctional (meth)acrylate such as
pentaerythritol tetra(meth)acrylate and ditrimethylol propane
tetra(meth)acrylate; a hexafunctional (meth)acrylate such as
dipentaerythritol hexa(meth)acrylate; and the like.
[0169] Among these (meth)acryl-based compounds, it is preferable to
use a (meth)acryl-based polyfunctional monomer. This makes it
possible for the spacer 104 to be obtained by exposing and
developing the spacer formation layer 12 to exhibit excellent
strength. As a result, a semiconductor device 100 provided with the
spacer 104 can have a more superior shape keeping property.
[0170] Further, by using the (meth)acryl-based polyfunctional
monomer, it is possible to reliably reduce the warpage of the
bonded body 2000. Further, it is also possible to reliably reduce
the warpage of the bonded body 2000 before the process (grinding
and/or polishing) of the semiconductor wafer 101' and to
effectively suppress the increasing rate of the warpage of the
bonded body 2000 after the process (grinding and/or polishing) of
the semiconductor wafer 101'. From the viewpoint of such a fact, it
is also preferable to use the (meth)acryl-based polyfunctional
monomer.
[0171] In this regard, it is to be noted that, in the present
specification, the (meth)acryl-based polyfunctional monomer means a
monomer of a (meth)acrylic acid ester containing three or more
acryloyl groups or methacryloyl groups.
[0172] Further, among the (meth)acryl-based polyfunctional
monomers, it is more preferable to use the trifunctional
(meth)acrylate or the tetrafunctional (meth)acrylate. This makes it
possible to exhibit the above effects more remarkably.
[0173] In this regard, in the case of using the (meth)acryl-based
polyfunctional monomer, it is preferred that the photo
polymerizable resin further contains an epoxy vinyl ester resin. In
this case, since the (meth)acryl-based polyfunctional monomer is
reacted with the epoxy vinyl ester resin by radical polymerization
when exposing the spacer formation layer 12, it is possible to more
effectively improve the strength of the spacer 104 to be formed by
being exposed and developed. On the other hand, it is possible to
improve solubility of the non-exposed region of the spacer
formation layer 12 with the alkali developer when developing it, to
thereby reduce residues after the development.
[0174] Examples of the epoxy vinyl ester resin include
2-hydroxyl-3-phenoxypropyl acrylate, EPOLIGHT 40E methacryl
addition product, EPOLIGHT 70P acrylic acid addition product,
EPOLIGHT 200P acrylic acid addition product, EPOLIGHT 80MF acrylic
acid addition product, EPOLIGHT 3002 methacrylic acid addition
product, EPOLIGHT 3002 acrylic acid addition product, EPOLIGHT 1600
acrylic acid addition product, bisphenol A diglycidyl ether
methacrylic acid addition product, bisphenol A diglycidyl ether
acrylic acid addition product, EPOLIGHT 200E acrylic acid addition
product, EPOLIGHT 400E acrylic acid addition product, and the
like.
[0175] In the case where the photo polymerizable resin contains the
(meth)acryl-based polyfunctional monomer, an amount of the
(meth)acryl-based polyfunctional monomer contained in the resin
composition is not limited to a specific value, but is preferably
in the range of about 1 to 50 wt %, and more preferably in the
range of about 5 to 25 wt % with respect to the total amount of the
resin composition. This makes it possible to more effectively
improve the strength of the spacer formation layer 12 after being
exposed, that is, the spacer 104, and thus to more effectively
improve the shape keeping property thereof when the transparent
substrate 102 is bonded to the semiconductor wafer 101'.
[0176] Further, in the case where the photo polymerizable resin
contains the epoxy vinyl ester resin in addition to the
(meth)acryl-based polyfunctional monomer, an amount of the epoxy
vinyl ester resin is not limited to a specific value, but is
preferably in the range of about 3 to 30 wt %, and more preferably
in the range of about 5 to 15 wt % with respect to the total amount
of the resin composition. This makes it possible to more
effectively reduce a residual ratio of residues attached to each
surface of the semiconductor wafer and transparent substrate after
the transparent substrate is bonded to the semiconductor wafer.
[0177] Furthermore, it is preferred that the above photo
polymerizable resin is of a liquid state at normal temperature.
This makes it possible to further improve curing reactivity of the
spacer formation layer by light irradiation (e.g., by ultraviolet
ray irradiation). In addition, it is possible to easily mix the
photo polymerizable resin with the other components (e.g., the
alkali soluble resin). Examples of the photo polymerizable resin in
the liquid form at the normal temperature include the above
ultraviolet curable resin containing the (meth)acryl-based compound
as the major component thereof, and the like.
[0178] In this regard, it is to be noted that a weight-average
molecular weight of the photo polymerizable resin is not limited to
a specific value, but is preferably 5,000 or less, and more
preferably in the range of about 150 to 3,000. If the
weight-average molecular weight falls within the above range,
sensitivity of the spacer formation layer 12 becomes specifically
higher. Further, the spacer formation layer 12 can also have
superior resolution.
[0179] Here, the weight-average molecular weight of the photo
polymerizable resin can be measured using the gel permeation
chromatographic method (GPC), and is calculated in the same manner
as described above.
[0180] (Dissolution Accelerator)
[0181] The resin composition to be used for forming the spacer
formation layer 12 may contain a dissolution accelerator. As the
dissolution accelerator, a compound including a hydroxyl group or a
carboxyl group is exemplified, phenols or a phenol resin is
especially preferable.
[0182] By adding the phenols or the phenol resin into the resin
composition, a concentration of phenolic hydroxyl groups contained
therein is increased. This makes it possible to improve
resolvability of the resin composition by the alkali developer.
After the phenols or the phenol resin functions as the dissolution
accelerator of the resin composition by the alkali developer, it is
introduced into a matrix of a cured product of the thermosetting
resin. Therefore, it is possible to suppress members to be bonded
such as the transparent substrate and the semiconductor wafer from
being contaminated and to prevent heat resistance and moisture
resistance from being lowered.
[0183] (Inorganic Filler)
[0184] In this regard, it is to be noted that the resin composition
constituting the spacer formation layer 12 may also contain an
inorganic filler. This makes it possible to further improve the
strength of the spacer 104 to be formed from the spacer formation
layer 12.
[0185] However, in the case where an amount of the inorganic filler
contained in the resin composition becomes too large, raised are
problems such as adhesion of foreign substances derived from the
inorganic filler onto the semiconductor wafer 101' and occurrence
of undercut after developing the spacer formation layer 12. For
this reason, it is preferred that the amount of the inorganic
filler contained in the resin composition is 9 wt % or less with
respect to the total amount of the resin composition.
[0186] Further, in the case where the resin composition contains
the (meth)acryl-based polyfunctional monomer as the photo
polymerizable resin, since it is possible to sufficiently improve
the strength of the spacer 104 to be formed by exposing and
developing the spacer formation layer 12 due to the addition of the
(meth)acryl-based polyfunctional monomer, the addition of the
inorganic filler to the resin composition can be omitted.
[0187] Examples of the inorganic filler include: a fibrous filler
such as an alumina fiber and a glass fiber; a needle filler such as
potassium titanate, wollastonite, aluminum borate, needle magnesium
hydroxide and whisker; a platy filler such as talc, mica, sericite,
a glass flake, scaly graphite and platy calcium carbonate; a
globular (granular) filler such as calcium carbonate, silica, fused
silica, baked clay and non-baked clay; a porous filler such as
zeolite and silica gel; and the like. These inorganic fillers may
be used alone or in combination of two or more of them. Among them,
it is preferable to use the porous filler.
[0188] An average particle size of the inorganic filler is not
limited to a specific value, but is preferably in the range of
about 0.01 to 90 .mu.m, and more preferably in the range of about
0.1 to 40 .mu.m. If the average particle size exceeds the upper
limit value, there is a fear that appearance and resolution of the
spacer formation layer 12 are lowered. On the other hand, if the
average particle size is less than the above lower limit value,
there is a fear that the transparent substrate 102 cannot be
reliably bonded to the spacer 104 even by the thermal bonding.
[0189] In this regard, it is to be noted that the average particle
size is measured using, for example, a particle size distribution
measurement apparatus of a laser diffraction type ("SALD-7000"
produced by Shimadzu Corporation).
[0190] Further, in the case where the porous filler is used as the
inorganic filler, an average hole size of the porous filler is
preferably in the range of about 0.1 to 5 nm, and more preferably
in the range of about 0.3 to 1 nm.
[0191] Here, by constituting the resin composition from the above
mentioned constituent material, an elastic modulus at 25.degree. C.
of the spacer 104 formed of such a resin composition can be set
preferably in the range of about 0.1 to 15 GPa, and more preferably
in the range of about 1 to 7 GPa. If the elastic modulus of the
spacer 104 falls within the above range, it is possible to more
reliably set the warpage of the bonded body 2000 to 3,000 .mu.m or
less.
[0192] Further, it is also possible to set the warpage of the
bonded body 2000 before the process (grinding and/or polishing)
thereof to 500 .mu.m or less and to set the increasing rate of the
warpage of the bonded body 2000 after the process thereof to 6000
or less.
[0193] For example, the elastic modulus at 25.degree. C. can be
obtained by measuring the elastic modulus of the resin composition
using a dynamic viscoelasticity apparatus ("RSA3" produced by TA
Instruments) at a temperature range of -30 to 200.degree. C., at a
temperature rising speed of 5.degree. C./min and at a frequency of
10 Hz, and reading a value of the elastic modulus measured at
25.degree. C.
[0194] Further, by constituting the resin composition from the
above mentioned constituent material, an average linear expansion
coefficient at a temperature range of 0 to 30.degree. C. of the
spacer 104 formed of such a resin composition can be set preferably
in the range of about 20 to 150 ppm/.degree. C., and more
preferably in the range of about 50 to 100 ppm/.degree. C. If the
linear expansion coefficient of the spacer 104 falls within the
above range, it is possible to more reliably set the warpage of the
bonded body 2000 to 3,000 .mu.m or less.
[0195] Further, it is also possible to set the warpage of the
bonded body 2000 before the process (grinding and/or polishing)
thereof to 500 .mu.m or less and to set the increasing rate of the
warpage of the bonded body 2000 after the process thereof to 600%
or less.
[0196] For example, the average linear expansion coefficient at 0
to 30.degree. C. can be obtained by measuring a dimensional change
amount of a measuring sample using a linear expansion coefficient
measuring apparatus ("TMA/SS6000, EXSTAR6000" produced by Seiko
Instruments Inc.) at -30 to 200.degree. C. and at a temperature
rising speed of 5.degree. C./min, and then comparing the
dimensional change amount of the measuring sample at 0 to
30.degree. C. with a size of the measuring sample before the
measurement.
[0197] Furthermore, by constituting the resin composition from the
above mentioned constituent material, the elastic modulus and the
linear expansion coefficient of the spacer 104 formed of such a
resin composition can be set to a value falling within the above
range. Therefore, a residual stress at 25.degree. C. of the spacer
104 can be set preferably in the range of about 0.1 to 150 MPa, and
more preferably in the range of about 0.1 to 100 MPa. If the
residual stress of the spacer 104 falls within the above range, it
is possible to more reliably set the warpage of the bonded body
2000 to 3,000 .mu.m or less.
[0198] Further, it is also possible to set the warpage of the
bonded body 2000 before the process (grinding and/or polishing)
thereof to 500 .mu.m or less and to set the increasing rate of the
warpage of the bonded body 2000 after the process thereof to 600%
or less.
[0199] For example, the residual stress at 25.degree. C. can be
obtained by forming a resin layer onto a bare silicon wafer having
8 inches (e.g., by laminating a resin film onto the bare silicon
wafer so that the resin film is attached to the bare silicon wafer,
by spin-coating a liquid resin onto the bare silicon wafer and then
drying it, or by printing the liquid resin onto the bare silicon
wafer), exposing the resin layer with a light having a wavelength
of 365 nm under the condition of 1,000 mJ/cm.sup.2, thermally
curing it under the conditions of 180.degree. C. and 2 hours to
prepare an evaluation sample, measuring warpage of the evaluation
sample using a surface roughness shape measuring apparatus
("SURFCOM1400D" produced by TOKYO SEIMITSU CO., LTD.), and then
carrying out calculation based on the following formulas (1) and
(2).
R=(a.sup.2+4X.sup.2)/8X (1)
.sigma.=[D.sup.2E/{6Rt(1-.upsilon.)}].times.9.8 (2)
[0200] where "X" is the warpage (mm), "a" is a measuring strength
(mm), "R" is a radius of curvature (mm), "D" is a thickness of the
bare silicon wafer (mm), "E" is an elastic modulus of silicon
(16,200 kg/mm.sup.2), "t" is a thickness of the resin layer (mm),
".upsilon." is Poisson's ratio (0.3) and ".sigma." is a residual
stress (MPa), respectively.
[0201] In this regard, this step [9] in which the lower surface 111
of the semiconductor wafer 101' is processed (ground and/or
polished) may be carried out prior to the thermal curing step
[8].
[0202] [10] Next, the lower surface (back side) 111 of the
semiconductor wafer 101', which has been ground and/or polished, is
further subjected to a process (this step is referred to as a back
side processing step).
[0203] Examples of such a process include formation of a circuit
(wiring) on the lower surface 111, connection of the solder bumps
106 shown in FIG. 3(c) on the lower surface 111 and the like.
[0204] [11] Next, the semiconductor wafer bonding product 1000 is
diced so as to correspond to each individual circuit formed on the
semiconductor wafer 101', that is, each air-gap portion 105 defined
by the spacer 104, to thereby obtain a plurality of semiconductor
devices 100 (this step is referred to as a dicing step).
[0205] For example, the dicing of the semiconductor wafer bonding
product is carried out by forming grooves 21 from a side of the
transparent substrate 102 using a dicing saw along the area where
the spacer 104 is formed, and then also forming grooves 21 from a
side of the semiconductor wafer 101' using the dicing saw so as to
correspond to the grooves 21.
[0206] Through the above steps, the semiconductor device 100 can be
manufactured.
[0207] In this way, by dicing the semiconductor wafer bonding
product 1000 to thereby obtain the plurality of semiconductor
devices 100 at the same time, it is possible to mass-produce the
semiconductor devices 100, and thus to improve productive
efficiency thereof.
[0208] In this regard, for example, by mounting the semiconductor
device 100 on a substrate provided with a circuit (patterned
wiring), the circuit formed on the substrate is electrically
connected to the circuit formed on the lower surface of the base
substrate 101 via the solder bumps 106.
[0209] Further, the semiconductor device 100 mounted on the support
substrate as described above can be widely used in electronics such
as a cellular telephone, a digital camera, a video camera and a
miniature camera.
[0210] In this regard, in this embodiment, the PLB step [3] in
which the spacer formation layer 12 is heated after itself has been
formed and the PEB step [5] in which the spacer formation layer 12
is heated after itself has been exposed are carried out, but these
steps may be omitted depending on the kinds of the resin
composition constituting the spacer formation layer 12 (that is,
the resin composition of the present invention).
[0211] Further, the semiconductor wafer bonding product 1000 may be
heated after the back grinding step [9] in which the lower surface
111 of the semiconductor wafer 101' is ground. By heating the
semiconductor wafer bonding product 1000 after the back grinding
step [9], it is possible to reliably reduce the residual stress
existing in the spacer 104, to thereby effectively suppress the
warpage of the semiconductor wafer bonding product 1000.
[0212] While the resin composition, the semiconductor wafer bonding
product and the semiconductor device of the present invention have
been described hereinabove, the present invention is not limited
thereto.
[0213] For example, the resin composition of the present invention
also can contain other components in addition to the above
mentioned components insofar as the purpose of the present
invention is not spoiled. Examples of the other components include
a plastic resin, a leveling agent, a defoaming agent or a coupling
agent and the like.
EXAMPLES
[0214] Hereinafter, description will be made on concrete examples
of the present invention.
[0215] [1] Manufacture of Semiconductor Wafer Bonding Product
[0216] In each of the following Examples and Comparative Examples,
5 bonded bodies and 5 semiconductor wafer bonding products were
manufactured as follows.
Example 1
1. Synthesis of Alkali Soluble Resin
Methacryloyl-Modified Bisphenol A Novolac Resin: MPN001
[0217] 500 g of a MEK (methyl ethyl ketone) solution containing a
novolac-type bisphenol A resin ("Phenolite LF-4871" produced by DIC
corporation) with a solid content of 60 wt % was added into a 2 L
flask. Thereafter, 1.5 g of tributylamine as a catalyst and 0.15 g
of hydroquinone as a polymerization inhibitor were added into the
flask, and then they were heated at 100.degree. C. Next, 180.9 g of
glycidyl methacrylate was further added into the flask in drop by
drop for 30 minutes, and then they were reacted with each other by
being stirred for 5 hours at 100.degree. C., to thereby obtain a
methacryloyl-modified bisphenol A novolac resin (methacryloyl
modified ratio: 50%) with a solid content of 74%.
2. Preparation of Resin Varnish Containing Resin Composition
Constituting Spacer Formation Layer
[0218] 30.0 wt % of the solid content of the above
methacryloyl-modified bisphenol A novolac resin (MPN001) as an
alkali soluble resin; 19.0 wt % of a cresol novolac-type epoxy
resin ("EPICLON N-665" produced by DIC Corporation) and 5.0 wt % of
a siloxane-modified epoxy resin ("BY16-115" produced by Dow Corning
Toray Co., Ltd.) as a thermosetting resin (epoxy resin); 10.0 wt %
of ethylene glycol dimethacrylate ("NK Ester A-200" produced by
Shin-Nakamura Chemical Co., Ltd.) as a photo polymerizable resin;
and 35.0 wt % of spherical silica having an average particle size
of 0.33 .mu.m and a maximum particle size of 0.8 .mu.m ("SFP-20M"
produced by DENKI KAGAKU KOGYO KABUSHIKI KAISHA) as an inorganic
filler were weighed, and methyl ethyl ketone ("MEK" produced by
DAISHIN CHEMICAL CO., LTD.) was added thereto so that an amount
(concentration) of the resin components contained in a resin
varnish finally obtained was adjusted to 71 wt %.
[0219] Thereafter, the above components were stirred until the
cresol novolac-type resin (EPICLON N-665) was dissolved
thereinto.
[0220] Next, the silica was dispersed thereinto using a bead mill
mixer (bead diameter: 400 .mu.m, processing speed: 6 g/s, 5
passes).
[0221] Next, 1.0 wt % of benzyl dimethyl ketal ("IRGACURE 651"
produced by Ciba Specialty Chemicals) as a photo initiator was
added thereinto, and they were stirred using a stirring blade (450
rpm) for 1 hour, to obtain a resin varnish.
3. Production of Spacer Formation Film
[0222] First, prepared was a polyester film having a thickness of
50 .mu.m ("MRX 50" produced by Mitsubishi Plastics, Inc.) as a
support base.
[0223] Next, the above prepared resin varnish was applied onto the
support base using a konma coater "MGF No. 194001 type 3-293"
produced by YASUI SEIKI) to form a coating film constituted from
the resin varnish. Thereafter, the formed coating film was dried
under the conditions of 80.degree. C. for 20 minutes to form a
spacer formation layer. In this way, the spacer formation film was
obtained. In the obtained spacer formation film, an average
thickness of the spacer formation layer was 50 .mu.m.
4. Manufacture of Bonded Body for Measuring Warpage
[0224] First, prepared was a semiconductor wafer having a
substantially circular shape and a diameter of 8 inches (Si wafer,
diameter: 20.3 cm, thickness: 725 .mu.m).
[0225] Next, the above produced spacer formation film was laminated
on the semiconductor wafer using a roll laminator under the
conditions in which a roll temperature was 60.degree. C., a roll
speed was 0.3 m/min and a syringe pressure was 2.0 kgf/cm.sup.2, to
thereby obtain the semiconductor wafer with the spacer formation
film.
[0226] Next, the semiconductor wafer with the spacer formation film
was irradiated with an ultraviolet ray (wavelength: 365 nm,
integrated dose: 700 mJ/cm.sup.2) from a side of the spacer
formation film so that the entirety of the spacer formation layer
at a planar view thereof was exposed, and then the support base was
removed therefrom.
[0227] Next, prepared was a transparent substrate (quartz glass
substrate, diameter: 20.3 mm, thickness: 350 .mu.m). This
transparent substrate was bonded to the semiconductor wafer, on
which a spacer had been formed, by compression bonding using a
substrate bonder ("SB8e" produced by Suss Microtec k.k.). In this
way, manufactured was a bonded body in which the transparent
substrate was bonded to the semiconductor wafer through the
spacer.
5. Manufacture of Semiconductor Wafer Bonding Product
[0228] First, prepared was a semiconductor wafer having a
substantially circular shape and a diameter of 8 inches (Si wafer,
diameter: 20.3 cm, thickness: 725 .mu.m).
[0229] Next, the above produced spacer formation film was laminated
on the semiconductor wafer using a roll laminator under the
conditions in which a roll temperature was 60.degree. C., a roll
speed was 0.3 m/min and a syringe pressure was 2.0 kgf/cm.sup.2, to
thereby obtain the semiconductor wafer with the spacer formation
film.
[0230] Next, the semiconductor wafer with the spacer formation film
was selectively irradiated with an ultraviolet ray (wavelength: 365
nm, integrated dose: 700 mJ/cm.sup.2) from a side of the spacer
formation film so that the spacer formation layer was exposed in a
grid pattern at a planar view thereof, and then the support base
was removed therefrom. In this regard, it is to be noted that when
exposing the spacer formation layer, 50% of the spacer formation
layer was exposed in a planar view thereof so that a width of a
region to be exposed in the grid pattern became 0.6 mm.
[0231] Next, the exposed spacer formation layer was developed using
2.38 wt % of tetramethyl ammonium hydroxide (TMAH) aqueous solution
as a developer (alkali solution) under the conditions in which a
developer pressure was 0.3 MPa and a developing time was 90
seconds. In this way, formed was a spacer composed of ribs each
having a width of 0.6 mm onto the semiconductor wafer.
[0232] Next, prepared was a transparent substrate (quartz glass
substrate, diameter: 20.3 mm, thickness: 350 .mu.m). This
transparent substrate was bonded to the semiconductor wafer, on
which the spacer had been formed, by compression bonding using a
substrate bonder ("SB8e" produced by Suss Microtec k.k.). In this
way, manufactured was a semiconductor wafer bonding product in
which the transparent substrate was bonded to the semiconductor
wafer through the spacer.
[0233] The obtained semiconductor wafer bonding product before a
process (grinding) thereof was placed on a flat surface so that the
transparent substrate is located on the downside, and then a
warpage thereof was measured.
6. Back Grinding of Semiconductor Wafer Bonding Product
[0234] The semiconductor wafer of the semiconductor wafer bonding
product was ground using a grinder ("DFG8540" produced by DISCO
Corporation) so that a thickness of a central portion of the
semiconductor wafer became 145 .mu.m.
[0235] Thereafter, the semiconductor wafer bonding product after
the process (grinding) thereof was also placed on the flat surface
so that the transparent substrate is located on the downside, and
then the warpage thereof was measured.
7. Dicing of Semiconductor Wafer Bonding Product
[0236] The ground semiconductor wafer bonding product was diced
using a dicing saw ("DFD6450" produced by DISCO Corporation) to
separate into chips each having a size of 7 mm.times.8 mm.
[0237] In this regard, it is to be noted that in the obtained
semiconductor wafer bonding product, an elastic modulus at
25.degree. C. of the spacer was 7.8 GPa, an average linear
expansion coefficient at 0 to 30.degree. C. thereof was 68
ppm/.degree. C. and a residual stress at 25.degree. C. thereof was
16 MPa.
Example 2
[0238] Bonded bodies and semiconductor wafer bonding products were
manufactured in the same manner as Example 1, except that the
preparation of the resin varnish (that is, the above step "2.") was
carried out as follows.
[0239] 40.0 wt % of the solid content the above
methacryloyl-modified bisphenol A novolac resin (MPN001) as the
alkali soluble resin; 19.0 wt % of the cresol novolac-type epoxy
resin ("EPICLON N-665" produced by DIC Corporation) and 3.0 wt % of
the siloxane-modified epoxy resin ("BY16-115" produced by Dow
Corning Toray Co., Ltd.) as the thermosetting resin (epoxy resin);
2.0 wt % of a phenol novolac resin ("PR-HF-6" produced by Sumitomo
Bakelite Co., Ltd.); 10.0 wt % of the ethylene glycol
dimethacrylate ("NK Ester A-200" produced by Shin-Nakamura Chemical
Co., Ltd.) as the photo polymerizable resin; and 25.0 wt % of the
spherical silica having the average particle size of 0.33 .mu.m and
the maximum particle size of 0.8 .mu.m ("SFP-20M" produced by DENKI
KAGAKU KOGYO KABUSHIKI KAISHA) as the inorganic filler were
weighed, and the methyl ethyl ketone ("MEK" produced by DAISHIN
CHEMICAL CO., LTD.) was added thereto so that an amount
(concentration) of the resin components contained in a resin
varnish finally obtained is adjusted to 71 wt %.
[0240] Thereafter, the above components were stirred until the
cresol novolac-type resin (EPICLON N-665) was dissolved
thereinto.
[0241] Next, the silica was dispersed thereinto using the bead mill
mixer (bead diameter: 400 .mu.m, processing speed: 6 g/s, 5
passes).
[0242] Next, 1.0 wt % of the benzyl dimethyl ketal ("IRGACURE 651"
produced by Ciba Specialty Chemicals) as the photo initiator was
added thereinto, and they were stirred using the stirring blade
(450 rpm) for 1 hour, to obtain a resin varnish.
[0243] In this regard, it is to be noted that in the obtained
semiconductor wafer bonding product, the elastic modulus at
25.degree. C. of the spacer was 3.0 GPa, the average linear
expansion coefficient at 0 to 30.degree. C. thereof was 70
ppm/.degree. C. and the residual stress at 25.degree. C. thereof
was 16 MPa.
Example 3
[0244] Bonded bodies and semiconductor wafer bonding products were
manufactured in the same manner as Example 1, except that the
preparation of the resin varnish (that is, the above step "2.") was
carried out as follows.
[0245] 55.0 wt % of the solid content of the above
methacryloyl-modified bisphenol A novolac resin (MPN001) as the
alkali soluble resin; 15.0 wt % of the cresol novolac-type epoxy
resin ("EPICLON N-665" produced by DIC Corporation) and 5.0 wt % of
the siloxane-modified epoxy resin ("BY16-115" produced by Dow
Corning Toray Co., Ltd.) as the thermosetting resin (epoxy resin);
7.0 wt % of the phenol novolac resin ("PR-HF-6" produced by
Sumitomo Bakelite Co., Ltd.); and 17.0 wt % of trimethylol propane
trimethacrylate ("NK Ester A-TMP" produced by Shin-Nakamura
Chemical Co., Ltd.) as the photo polymerizable resin were weighed,
and the methyl ethyl ketone ("MEK" produced by DAISHIN CHEMICAL
CO., LTD.) was added thereto so that an amount (concentration) of
the resin components contained in a resin varnish finally obtained
is adjusted to 71 wt %.
[0246] Thereafter, the above components were stirred until the
cresol novolac-type resin (EPICLON N-665) was dissolved
thereinto.
[0247] Next, 1.0 wt % of the benzyl dimethyl ketal ("IRGACURE 651"
produced by Ciba Specialty Chemicals) as the photo initiator was
added thereinto, and they were stirred using the stirring blade
(450 rpm) for 1 hour, to obtain a resin varnish.
[0248] In this regard, it is to be noted that in the obtained
semiconductor wafer bonding product, the elastic modulus at
25.degree. C. of the spacer was 2.4 GPa, the average linear
expansion coefficient at 0 to 30.degree. C. thereof was 84
ppm/.degree. C. and the residual stress at 25.degree. C. thereof
was 18 MPa.
Example 4
[0249] Bonded bodies and semiconductor wafer bonding products were
manufactured in the same manner as Example 1, except that the
preparation of the resin varnish (that is, the above step "2.") was
carried out as follows.
[0250] 45.0 wt % of the solid content of the above
methacryloyl-modified bisphenol A novolac resin (MPN001) as the
alkali soluble resin; 27.0 wt % of the cresol novolac-type epoxy
resin ("EPICLON N-665" produced by DIC Corporation) and 3.0 wt % of
the siloxane-modified epoxy resin ("BY16-115" produced by Dow
Corning Toray Co., Ltd.) as the thermosetting resin (epoxy resin);
and 23.0 wt % of the tetramethylol methane tetraacrylate ("NK Ester
A-TMMT" produced by Shin-Nakamura Chemical Co., Ltd.) as the photo
polymerizable resin were weighed, and the methyl ethyl ketone
("MEK" produced by DAISHIN CHEMICAL CO., LTD.) was added thereto so
that an amount (concentration) of the resin components contained in
a resin varnish finally obtained is adjusted to 71 wt %.
[0251] Thereafter, the above components were stirred until the
cresol novolac-type resin (EPICLON N-665) was dissolved
thereinto.
[0252] Next, 2.0 wt % of the benzyl dimethyl ketal ("IRGACURE 651"
produced by Ciba Specialty Chemicals) as the photo initiator was
added thereinto, and they were stirred using the stirring blade
(450 rpm) for 1 hour, to obtain a resin varnish.
[0253] In this regard, it is to be noted that in the obtained
semiconductor wafer bonding product, the elastic modulus at
25.degree. C. of the spacer was 5.1 GPa, the average linear
expansion coefficient at 0 to 30.degree. C. thereof was 95
ppm/.degree. C. and the residual stress at 25.degree. C. thereof
was 63 MPa.
Example 5
[0254] Bonded bodies and semiconductor wafer bonding products were
manufactured in the same manner as Example 1, except that the
preparation of the resin varnish (that is, the above step "2.") was
carried out as follows.
[0255] 45.0 wt % of the solid content of the above
methacryloyl-modified bisphenol A novolac resin (MPN001) as the
alkali soluble resin; 30.0 wt % of the cresol novolac-type epoxy
resin ("EPICLON N-665" produced by DIC Corporation) and 8.0 wt % of
the siloxane-modified epoxy resin ("BY16-115" produced by Dow
Corning Toray Co., Ltd.) as the thermosetting resin (epoxy resin);
and 15.0 wt % of the tetramethylol methane tetraacrylate ("NK Ester
A-TMMT" produced by Shin-Nakamura Chemical Co., Ltd.) as the photo
polymerizable resin were weighed, and the methyl ethyl ketone
("MEK" produced by DAISHIN CHEMICAL CO., LTD.) was added thereto so
that an amount (concentration) of the resin components contained in
a resin varnish finally obtained is adjusted to 71 wt %.
[0256] Thereafter, the above components were stirred until the
cresol novolac-type resin (EPICLON N-665) was dissolved
thereinto.
[0257] Next, 2.0 wt % of the benzyl dimethyl ketal ("IRGACURE 651"
produced by Ciba Specialty Chemicals) as the photo initiator was
added thereinto, and they were stirred using the stirring blade
(450 rpm) for 1 hour, to obtain a resin varnish.
[0258] In this regard, it is to be noted that in the obtained
semiconductor wafer bonding product, the elastic modulus at
25.degree. C. of the spacer was 4.5 GPa, the average linear
expansion coefficient at 0 to 30.degree. C. thereof was 91
ppm/.degree. C. and the residual stress at 25.degree. C. thereof
was 32 MPa.
Example 6
[0259] Bonded bodies and semiconductor wafer bonding products were
manufactured in the same manner as Example 1, except that the
preparation of the resin varnish (that is, the above step "2.") was
carried out as follows.
[0260] 45.0 wt % of the solid content of the above
methacryloyl-modified bisphenol A novolac resin (MPN001) as the
alkali soluble resin; 30.0 wt % of the cresol novolac-type epoxy
resin ("EPICLON N-665" produced by DIC Corporation) and 8.0 wt % of
the siloxane-modified epoxy resin ("BY16-115" produced by Dow
Corning Toray Co., Ltd.) as the thermosetting resin (epoxy resin);
and 15.0 wt % of dipentaerythritol hexaacrylate ("LIGHT-ACRYLATE
DPE-6A" produced by KYOEISHA CHEMICAL Co., LTD.) as the photo
polymerizable resin were weighed, and the methyl ethyl ketone
("MEK" produced by DAISHIN CHEMICAL CO., LTD.) was added thereto so
that an amount (concentration) of the resin components contained in
a resin varnish finally obtained is adjusted to 71 wt %.
[0261] Thereafter, the above components were stirred until the
cresol novolac-type resin (EPICLON N-665) was dissolved
thereinto.
[0262] Next, 2.0 wt % of the benzyl dimethyl ketal ("IRGACURE 651"
produced by Ciba Specialty Chemicals) as the photo initiator was
added thereinto, and they were stirred using the stirring blade
(450 rpm) for 1 hour, to obtain a resin varnish.
[0263] In this regard, it is to be noted that in the obtained
semiconductor wafer bonding product, the elastic modulus at
25.degree. C. of the spacer was 3.8 GPa, the average linear
expansion coefficient at 0 to 30.degree. C. thereof was 89
ppm/.degree. C. and the residual stress at 25.degree. C. thereof
was 43 MPa.
Example 7
[0264] Bonded bodies and semiconductor wafer bonding products were
manufactured in the same manner as Example 1, except that the
preparation of the resin varnish (that is, the above step "2.") was
carried out as follows.
[0265] 45.0 wt % of the solid content of the above
methacryloyl-modified bisphenol A novolac resin (MPN001) as the
alkali soluble resin; 30.0 wt % of the cresol novolac-type epoxy
resin ("EPICLON N-665" produced by DIC Corporation) and 8.0 wt % of
the siloxane-modified epoxy resin ("BY16-115" produced by Dow
Corning Toray Co., Ltd.) as the thermosetting resin (epoxy resin);
and 15.0 wt % of the ethylene glycol dimethacrylate ("NK Ester
A-200" produced by Shin-Nakamura Chemical Co., Ltd.) as the photo
polymerizable resin were weighed, and the methyl ethyl ketone
("MEK" produced by DAISHIN CHEMICAL CO., LTD.) was added thereto so
that an amount (concentration) of the resin components contained in
a resin varnish finally obtained is adjusted to 71 wt %.
[0266] Thereafter, the above components were stirred until the
cresol novolac-type resin (EPICLON N-665) was dissolved
thereinto.
[0267] Next, 2.0 wt % of the benzyl dimethyl ketal ("IRGACURE 651"
produced by Ciba Specialty Chemicals) as the photo initiator was
added thereinto, and they were stirred using the stirring blade
(450 rpm) for 1 hour, to obtain a resin varnish.
[0268] In this regard, it is to be noted that in the obtained
semiconductor wafer bonding product, the elastic modulus at
25.degree. C. of the spacer was 1.4 GPa, the average linear
expansion coefficient at 0 to 30.degree. C. thereof was 93
ppm/.degree. C. and the residual stress at 25.degree. C. thereof
was 23 MPa.
Example 8
[0269] Bonded bodies and semiconductor wafer bonding products were
manufactured in the same manner as Example 1, except that the
preparation of the resin varnish (that is, the above step "2.") was
carried out as follows.
[0270] 20.0 wt % of the solid content of the above
methacryloyl-modified bisphenol A novolac resin (MPN001) as the
alkali soluble resin; 14.0 wt % of the cresol novolac-type epoxy
resin ("EPICLON N-665" produced by DIC Corporation) and 3.0 wt % of
the siloxane-modified epoxy resin ("BY16-115" produced by Dow
Corning Toray Co., Ltd.) as the thermosetting resin (epoxy resin);
7.0 wt % of the ethylene glycol dimethacrylate ("NK Ester A-200"
produced by Shin-Nakamura Chemical Co., Ltd.) as the photo
polymerizable resin; and 55.0 wt % of the spherical silica having
the average particle size of 0.33 .mu.m and the maximum particle
size of 0.8 .mu.m ("SFP-20M" produced by DENKI KAGAKU KOGYO
KABUSHIKI KAISHA) as the inorganic filler were weighed, and methyl
ethyl ketone ("MEK" produced by DAISHIN CHEMICAL CO., LTD.) was
added thereto so that an amount (concentration) of the resin
components contained in a resin varnish finally obtained is
adjusted to 71 wt %.
[0271] Thereafter, the above components were stirred until the
cresol novolac-type resin (EPICLON N-665) was dissolved
thereinto.
[0272] Next, the silica was dispersed thereinto using the bead mill
mixer (bead diameter: 400 .mu.m, processing speed: 6 g/s, 5
passes).
[0273] Next, 1.0 wt % of the benzyl dimethyl ketal ("IRGACURE 651"
produced by Ciba Specialty Chemicals) as the photo initiator was
added thereinto, and they were stirred using the stirring blade
(450 rpm) for 1 hour, to obtain a resin varnish.
[0274] In this regard, it is to be noted that in the obtained
semiconductor wafer bonding product, the elastic modulus at
25.degree. C. of the spacer was 9.9 GPa, the average linear
expansion coefficient at 0 to 30.degree. C. thereof was 49
ppm/.degree. C. and the residual stress at 25.degree. C. thereof
was 9 MPa.
Example 9
[0275] Bonded bodies and semiconductor wafer bonding products were
manufactured in the same manner as Example 1, except that the
preparation of the resin varnish (that is, the above step "2.") was
carried out as follows.
[0276] 25.0 wt % of the solid content of the above
methacryloyl-modified bisphenol A novolac resin (MPN001) as the
alkali soluble resin; 16.0 wt % of the cresol novolac-type epoxy
resin ("EPICLON N-665" produced by DIC Corporation) and 4.0 wt % of
the siloxane-modified epoxy resin ("BY16-115" produced by Dow
Corning Toray Co., Ltd.) as the thermosetting resin (epoxy resin);
8.0 wt % of the ethylene glycol dimethacrylate ("NK Ester A-200"
produced by Shin-Nakamura Chemical Co., Ltd.) as the photo
polymerizable resin; and 45.0 wt % of the spherical silica having
the average particle size of 0.33 .mu.m and the maximum particle
size of 0.8 .mu.m ("SFP-20M" produced by DENKI KAGAKU KOGYO
KABUSHIKI KAISHA) as the inorganic filler were weighed, and the
methyl ethyl ketone ("MEK" produced by DAISHIN CHEMICAL CO., LTD.)
was added thereto so that an amount (concentration) of the resin
components contained in a resin varnish finally obtained is
adjusted to 71 wt %.
[0277] Thereafter, the above components were stirred until the
cresol novolac-type resin (EPICLON N-665) was dissolved
thereinto.
[0278] Next, the silica was dispersed thereinto using the bead mill
mixer (bead diameter: 400 .mu.m, processing speed: 6 g/s, 5
passes).
[0279] Next, 2.0 wt % of the benzyl dimethyl ketal ("IRGACURE 651"
produced by Ciba Specialty Chemicals) as the photo initiator was
added thereinto, and they were stirred using the stirring blade
(450 rpm) for 1 hour, to obtain a resin varnish.
[0280] In this regard, it is to be noted that in the obtained
semiconductor wafer bonding product, the elastic modulus at
25.degree. C. of the spacer was 8.5 GPa, the average linear
expansion coefficient at 0 to 30.degree. C. thereof was 60
ppm/.degree. C. and the residual stress at 25.degree. C. thereof
was 11 MPa.
Comparative Example 1
[0281] Bonded bodies and semiconductor wafer bonding products were
manufactured in the same manner as Example 1, except that the
preparation of the resin varnish (that is, the above step "2.") was
carried out as follows.
[0282] 35.0 wt % of the solid content of the above
methacryloyl-modified bisphenol A novolac resin (MPN001) as the
alkali soluble resin; and 63.0 wt % of the dipentaerythritol
hexaacrylate ("LIGHT-ACRYLATE DPE-6A" produced by KYOEISHA CHEMICAL
Co., LTD.) as the photo polymerizable resin were weighed, and the
methyl ethyl ketone ("MEK" produced by DAISHIN CHEMICAL CO., LTD.)
was added thereto so that an amount (concentration) of the resin
components contained in a resin varnish finally obtained is
adjusted to 71 wt %.
[0283] Next, 2.0 wt % of the benzyl dimethyl ketal ("IRGACURE 651"
produced by Ciba Specialty Chemicals) as the photo initiator was
added thereinto, and they were stirred using the stirring blade
(450 rpm) for 1 hour, to obtain a resin varnish.
[0284] In this regard, it is to be noted that in the obtained
semiconductor wafer bonding product, the elastic modulus at
25.degree. C. of the spacer was 5.2 GPa, the average linear
expansion coefficient at 0 to 30.degree. C. thereof was 118
ppm/.degree. C. and the residual stress at 25.degree. C. thereof
was 107 MPa.
Comparative Example 2
[0285] Bonded bodies and semiconductor wafer bonding products were
manufactured in the same manner as Example 1, except that the
preparation of the resin varnish (that is, the above step "2.") was
carried out as follows.
[0286] 45.0 wt % of the solid content of the above
methacryloyl-modified bisphenol A novolac resin (MPN001) as the
alkali soluble resin; and 53.0 wt % of the dipentaerythritol
hexaacrylate ("LIGHT-ACRYLATE DPE-6A" produced by KYOEISHA CHEMICAL
Co., LTD.) as the photo polymerizable resin were weighed, and the
methyl ethyl ketone ("MEK" produced by DAISHIN CHEMICAL CO., LTD.)
was added thereto so that an amount (concentration) of the resin
components contained in a resin varnish finally obtained is
adjusted to 71 wt %.
[0287] Next, 2.0 wt % of the benzyl dimethyl ketal ("IRGACURE 651"
produced by Ciba Specialty Chemicals) as the photo initiator was
added thereinto, and they were stirred using the stirring blade
(450 rpm) for 1 hour, to obtain a resin varnish.
[0288] In this regard, it is to be noted that in the obtained
semiconductor wafer bonding product, the elastic modulus at
25.degree. C. of the spacer was 5.0 GPa, the average linear
expansion coefficient at 0 to 30.degree. C. thereof was 101
ppm/.degree. C. and the residual stress at 25.degree. C. thereof
was 90 MPa.
[0289] In Table 1, indicated is the amount (wt %) of each component
contained in the resin composition constituting the spacer
formation layer obtained in each of Examples and Comparative
Examples.
TABLE-US-00001 TABLE 1 Ex. Com. Ex. 1 2 3 4 5 6 7 8 9 1 2 Alkali
Methacryloyl- 30.0 40.0 55.0 45.0 45.0 45.0 45.0 20.0 25.0 35.0
45.0 soluble modified resin bisphenol A novolac resin Thermo-
Cresol "EPICLON N-665" 19.0 19.0 15.0 27.0 30.0 30.0 30.0 14.0 16.0
setting novolac-type DIC Corporation resin epoxy resin Siloxane-
"BY16-115" 5.0 3.0 5.0 3.0 8.0 8.0 8.0 3.0 4.0 modified epoxy Dow
Cornng Toray resin Co., Ltd. Photo Ethylene glycol "NK Ester A-200"
10.0 10.0 15.0 7.0 8.0 polymerizable dimethacrylate Shin-Nakamura
resin Chemical Co., Ltd. Trimethylol "NK Ester A-TMP" 17.0 propane
Shin-Nakamura trimethacrylate Chemical Co., Ltd. Tetramethylol "NK
Ester A-TMMT" 23.0 15.0 methane Shin-Nakamura tetraacrylate
Chemical Co., Ltd. Dipenta- "LIGHT-ACRYLATE 15.0 63.0 53.0
erythritol DPE-6A" hexaacrylate KYOEISHA CHEMICAL Co., LTD. Photo
Benzyl dimethyl "IRGACURE 651" 1.0 1.0 1.0 2.0 2.0 2.0 2.0 1.0 2.0
2.0 2.0 initiator ketal Ciba Specialty Chemicals Dissolution Phenol
novolac "PR-HF-6" 2.0 7.0 accelerator resin Sumitomo Bakelite Co.,
Ltd. Filler Silica "SFP-20M" 35.0 25.0 55.0 45.0 DENKI KAGAKU KOGYO
KABUSHIKI KAISHA Total 100.0 100.0 100.0 100.0 100.0 100.0 100.0
100.0 100.0 100.0 100.0
[0290] [2] Evaluation of Warp of Bonded Body
[0291] First, each of the bonded bodies obtained in Examples and
Comparative Examples was heated under the conditions of 150.degree.
C. and 90 minutes. In this way, the spacer of each of the bonded
bodies was thermally cured.
[0292] On each of the bonded bodies obtained in Examples and
Comparative Examples after the spacer was thermally cured, a
warpage thereof was measured using a surface roughness measuring
apparatus ("surfcom 1400D-64" produced by TOKYO SEIMITSU CO.,
LTD.).
[0293] Next, on each of the bonded bodies obtained in Examples and
Comparative Examples, a lower surface (back side) of the
semiconductor wafer thereof was ground using a grinder ("DFG8540"
produced by DISCO Corporation) so that a thickness of a central
portion of the semiconductor wafer became 145 .mu.m. Namely, the
semiconductor wafer was ground so as to have one-fifth
thickness.
[0294] Thereafter, the warpage of each of the bonded bodies after
the grinding (back grinding) was measured in the same manner as
described above.
[0295] In the following Table 2, indicated is the warpage of each
of the bonded bodies obtained in Examples and Comparative Examples
before and after the back grinding thereof, respectively.
[0296] In this regard, it is to be noted that the warpage is an
average value of values measured in 5 bonded bodies obtained in
each of Examples and Comparative Examples.
[0297] [3] Evaluation of Influence on Bonded Body by Back
Grinding
[0298] In Examples and Comparative Examples, after each of the
bonded bodies passed through the above step "5." was back ground in
the above step "6.", influence on the bonded body by the back
grinding was evaluated as follows.
[0299] Namely, after each of the bonded bodies obtained in Examples
and Comparative Examples was back ground, thicknesses of the
semiconductor wafer thereof was measured at arbitrary 10 points,
and then the influence on the bonded body by the back grinding was
evaluated based on the following evaluation criteria.
[0300] A: Variation in the thicknesses of the semiconductor wafer
after the grinding (that is, a difference between a maximum value
and a minimum value thereof) is less than 10 .mu.m.
[0301] B: Variation in the thicknesses of the semiconductor wafer
after the grinding is in the range of 10 to 30 .mu.m within which a
problem would not practically occur.
[0302] C: Variation in the thicknesses of the semiconductor wafer
after the grinding is 30 .mu.m or more.
[0303] [4] Ease of Dicing of Semiconductor Wafer Bonding
Product
[0304] In Examples and Comparative Examples, after each of the
semiconductor wafer bonding products passed through the above steps
"5." and "6." was diced in the above step "7.", ease of dicing of
the semiconductor wafer bonding products was evaluated as
follows.
[0305] A: A yield of dicing the semiconductor wafer bonding
products is 95% or more.
[0306] B: A yield of dicing the semiconductor wafer bonding
products is in the range of 90% or more but less than 95%.
[0307] C: The semiconductor wafer bonding products could not be
transferred using a suction tool due to the warp thereof.
[0308] The evaluation results of the evaluations [2] to [4] carried
out in the above ways are indicated in Table 2.
[0309] Further, on each of the bonded bodies obtained in Examples
and Comparative Examples, according to the warpage thereof
indicated in Table 2, an increasing ratio of the warpage of the
bonded body after the back grinding thereof with respect to the
warpage of the bonded body before the back grinding thereof was
calculated.
[0310] This result is also indicated in the following Table 2.
TABLE-US-00002 TABLE 2 Ex. Com. Ex. 1 2 3 4 5 6 7 8 9 1 2 Warpage
before process 130 170 180 410 340 330 240 45 60 610 470 [.mu.m]
Warpage after process 330 380 520 1210 840 890 640 280 310 -- 3380
[.mu.m] Increasing ratio of 154 124 189 195 147 170 167 522 417 --
619 warpage after process [%] Elastic modulus at 25.degree. C. 7.8
3.0 2.4 5.1 4.5 3.8 1.4 9.9 8.5 5.2 5.0 [GPa] Average linear
expansion 68 70 84 95 91 89 93 49 60 118 101 coefficient (0 to
30.degree. C.) Residual stress [MPa] 16 16 18 63 32 43 23 9 11 107
90 Influence by back grinding A A A B A A A A A C B Dicing property
A A A B B B A A A -- C
[0311] As shown in Table 2, obtained is a result that the warpage
of each of the bonded bodies obtained in Examples after the
grinding thereof is suppressed to 3,000 .mu.m or less. Further,
obtained is a result that the warpage of each of the bonded bodies
obtained in Examples before the grinding thereof is suppressed to
500 .mu.m or less and the increasing ratio of the warpage of each
of the bonded bodies after the back grinding thereof is suppressed
to 600% or less.
[0312] On the other hand, the warpage of each of the bonded bodies
obtained in Comparative Example 1 before the back grinding thereof
exceeded 500 .mu.m, and thus each boded body could not be set to a
back grinding machine.
[0313] Further, the warpage of each of the bonded bodies obtained
in Comparative Example 2 exceeded 3,000 .mu.m and the increasing
ratio of the warpage of each boded body after the back grinding
thereof exceeded 600%, and thus each boded body could not be
transferred using the suction tool of the dicing machine.
[0314] For these results, it appears that by forming the spacer
using the resin composition constituted from the material
containing the alkali soluble resin, the thermosetting resin and
the photo initiator, the warpage of the bonded body after the
grinding thereof is suppressed to 3,000 .mu.m or less. Further, by
doing so, it also appears that the warpage of the bonded body
before the grinding thereof is suppressed to 500 .mu.m or less and
the increasing ratio of the warpage of the bonded body after the
back grinding thereof is suppressed to 600% or less.
[0315] Further, by suppressing the warpage of the bonded body after
the grinding thereof to 3,000 .mu.m or less, or by suppressing the
warpage of the bonded body before the grinding thereof to 500 .mu.m
or less and the increasing ratio of the warpage of the bonded body
after the back grinding thereof to 6000 or less, it is be
understood that the semiconductor wafer bonding product can be
diced in a high yield.
INDUSTRIAL APPLICABILITY
[0316] According to the present invention, in the case where a
semiconductor wafer having a substantially circular shape, a
diameter of 8 inches and a thickness of 725 .mu.m and a transparent
substrate having a substantially circular shape, a diameter of 8
inches and a thickness of 350 .mu.m are bonded together through a
spacer formed on a substantially overall surface of the
semiconductor wafer or the transparent substrate to thereby obtain
a bonded body, a surface of the semiconductor wafer opposite to the
spacer is subjected to a process for substantially uniformly
grinding and/or polishing it so that the semiconductor wafer has
one-fifth thickness, a warpage of the bonded body is suppressed to
3,000 .mu.m or less.
[0317] Therefore, it is possible to effectively suppress or prevent
a semiconductor wafer bonding product from being not set to a
machine for carrying out a back side processing step or a dicing
step or from being broken by being hooked into the machine.
[0318] Further, according to the present invention, the warpage of
the bonded body before the process thereof is suppressed to 500
.mu.m or less, and an increasing ratio of the warpage of the bonded
body after the process thereof is suppressed to 600% or less.
Therefore, it is possible to prevent the semiconductor wafer
bonding product from being not received into a magazine case to be
used for setting it to the above machine in the back side
processing step or the dicing step setting. Further, it is also
possible to prevent the semiconductor wafer bonding product from
being not sucked inside the machine, to thereby smoothly proceed
with the process thereof. Such a present invention provides
industrial applicability.
* * * * *